// Slower C++ solution:
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return true; } return false; }

template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return true; } return false; }

#define all(x) (x).begin(),(x).end()

#define fi first

#define se second

#define mp make_pair

#define si(x) int(x.size())

const int mod=1000000007,MAX=100005,INF=1<<30;



ll inv[MAX],fac[MAX],finv[MAX];



void make(){

    

    fac[0]=fac[1]=1;

    finv[0]=finv[1]=1;

    inv[1]=1;

    

    for(int i=2;i<MAX;i++){

        inv[i]=mod-inv[mod%i]*(mod/i)%mod;

        fac[i]=fac[i-1]*(ll)i%mod;

        finv[i]=finv[i-1]*inv[i]%mod;

    }

    

}



ll comb(ll a,ll b){

    if(a<b) return 0;

    return fac[a]*(finv[b]*finv[a-b]%mod)%mod;

}



ll perm(ll a,ll b){

    if(a<b) return 0;

    return fac[a]*finv[a-b]%mod;

}



int main(){

    

    std::ifstream in("text.txt");

    std::cin.rdbuf(in.rdbuf());

    cin.tie(0);

    ios::sync_with_stdio(false);

    

    int S;cin>>S;

    

    make();

    

    ll ans=0;

    

    for(int i=1;i<=S/3;i++){

        ans+=comb(S-i*3+i-1,i-1);

        ans%=mod;

    }

    

    cout<<ans<<endl;

    

}


// Faster C++ solution for the same problem (measured speedup: 3.135204802733176x):
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return true; } return false; }

template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return true; } return false; }

#define all(x) (x).begin(),(x).end()

#define fi first

#define se second

#define mp make_pair

#define si(x) int(x.size())



//短い版



#include <algorithm>

#include <array>



#ifdef _MSC_VER

#include <intrin.h>

#endif



namespace atcoder {

    

    namespace internal {

        

        int ceil_pow2(int n) {

            int x = 0;

            while ((1U << x) < (unsigned int)(n)) x++;

            return x;

        }

        

        int bsf(unsigned int n) {

#ifdef _MSC_VER

            unsigned long index;

            _BitScanForward(&index, n);

            return index;

#else

            return __builtin_ctz(n);

#endif

        }

        

    }  // namespace internal

    

}  // namespace atcoder







#include <utility>



namespace atcoder {

    

    namespace internal {

        

        constexpr long long safe_mod(long long x, long long m) {

            x %= m;

            if (x < 0) x += m;

            return x;

        }

        

        struct barrett {

            unsigned int _m;

            unsigned long long im;

            

            barrett(unsigned int m) : _m(m), im((unsigned long long)(-1) / m + 1) {}

            

            unsigned int umod() const { return _m; }

            

            unsigned int mul(unsigned int a, unsigned int b) const {

                

                unsigned long long z = a;

                z *= b;

#ifdef _MSC_VER

                unsigned long long x;

                _umul128(z, im, &x);

#else

                unsigned long long x =

                (unsigned long long)(((unsigned __int128)(z)*im) >> 64);

#endif

                unsigned int v = (unsigned int)(z - x * _m);

                if (_m <= v) v += _m;

                return v;

            }

        };

        

        constexpr long long pow_mod_constexpr(long long x, long long n, int m) {

            if (m == 1) return 0;

            unsigned int _m = (unsigned int)(m);

            unsigned long long r = 1;

            unsigned long long y = safe_mod(x, m);

            while (n) {

                if (n & 1) r = (r * y) % _m;

                y = (y * y) % _m;

                n >>= 1;

            }

            return r;

        }

        

        constexpr bool is_prime_constexpr(int n) {

            if (n <= 1) return false;

            if (n == 2 || n == 7 || n == 61) return true;

            if (n % 2 == 0) return false;

            long long d = n - 1;

            while (d % 2 == 0) d /= 2;

            for (long long a : {2, 7, 61}) {

                long long t = d;

                long long y = pow_mod_constexpr(a, t, n);

                while (t != n - 1 && y != 1 && y != n - 1) {

                    y = y * y % n;

                    t <<= 1;

                }

                if (y != n - 1 && t % 2 == 0) {

                    return false;

                }

            }

            return true;

        }

        template <int n> constexpr bool is_prime = is_prime_constexpr(n);

        

        constexpr std::pair<long long, long long> inv_gcd(long long a, long long b) {

            a = safe_mod(a, b);

            if (a == 0) return {b, 0};

            

            long long s = b, t = a;

            long long m0 = 0, m1 = 1;

            

            while (t) {

                long long u = s / t;

                s -= t * u;

                m0 -= m1 * u;  // |m1 * u| <= |m1| * s <= b

                

                

                auto tmp = s;

                s = t;

                t = tmp;

                tmp = m0;

                m0 = m1;

                m1 = tmp;

            }

            if (m0 < 0) m0 += b / s;

            return {s, m0};

        }

        

        constexpr int primitive_root_constexpr(int m) {

            if (m == 2) return 1;

            if (m == 167772161) return 3;

            if (m == 469762049) return 3;

            if (m == 754974721) return 11;

            if (m == 998244353) return 3;

            int divs[20] = {};

            divs[0] = 2;

            int cnt = 1;

            int x = (m - 1) / 2;

            while (x % 2 == 0) x /= 2;

            for (int i = 3; (long long)(i)*i <= x; i += 2) {

                if (x % i == 0) {

                    divs[cnt++] = i;

                    while (x % i == 0) {

                        x /= i;

                    }

                }

            }

            if (x > 1) {

                divs[cnt++] = x;

            }

            for (int g = 2;; g++) {

                bool ok = true;

                for (int i = 0; i < cnt; i++) {

                    if (pow_mod_constexpr(g, (m - 1) / divs[i], m) == 1) {

                        ok = false;

                        break;

                    }

                }

                if (ok) return g;

            }

        }

        template <int m> constexpr int primitive_root = primitive_root_constexpr(m);

        

    }  // namespace internal

    

}  // namespace atcoder





#include <cassert>

#include <numeric>

#include <type_traits>



namespace atcoder {

    

    namespace internal {

        

#ifndef _MSC_VER

        template <class T>

        using is_signed_int128 =

        typename std::conditional<std::is_same<T, __int128_t>::value ||

        std::is_same<T, __int128>::value,

        std::true_type,

        std::false_type>::type;

        

        template <class T>

        using is_unsigned_int128 =

        typename std::conditional<std::is_same<T, __uint128_t>::value ||

        std::is_same<T, unsigned __int128>::value,

        std::true_type,

        std::false_type>::type;

        

        template <class T>

        using make_unsigned_int128 =

        typename std::conditional<std::is_same<T, __int128_t>::value,

        __uint128_t,

        unsigned __int128>;

        

        template <class T>

        using is_integral = typename std::conditional<std::is_integral<T>::value ||

        is_signed_int128<T>::value ||

        is_unsigned_int128<T>::value,

        std::true_type,

        std::false_type>::type;

        

        template <class T>

        using is_signed_int = typename std::conditional<(is_integral<T>::value &&

                                                         std::is_signed<T>::value) ||

        is_signed_int128<T>::value,

        std::true_type,

        std::false_type>::type;

        

        template <class T>

        using is_unsigned_int =

        typename std::conditional<(is_integral<T>::value &&

                                   std::is_unsigned<T>::value) ||

        is_unsigned_int128<T>::value,

        std::true_type,

        std::false_type>::type;

        

        template <class T>

        using to_unsigned = typename std::conditional<

        is_signed_int128<T>::value,

        make_unsigned_int128<T>,

        typename std::conditional<std::is_signed<T>::value,

        std::make_unsigned<T>,

        std::common_type<T>>::type>::type;

        

#else

        

        template <class T> using is_integral = typename std::is_integral<T>;

        

        template <class T>

        using is_signed_int =

        typename std::conditional<is_integral<T>::value && std::is_signed<T>::value,

        std::true_type,

        std::false_type>::type;

        

        template <class T>

        using is_unsigned_int =

        typename std::conditional<is_integral<T>::value &&

        std::is_unsigned<T>::value,

        std::true_type,

        std::false_type>::type;

        

        template <class T>

        using to_unsigned = typename std::conditional<is_signed_int<T>::value,

        std::make_unsigned<T>,

        std::common_type<T>>::type;

        

#endif

        

        template <class T>

        using is_signed_int_t = std::enable_if_t<is_signed_int<T>::value>;

        

        template <class T>

        using is_unsigned_int_t = std::enable_if_t<is_unsigned_int<T>::value>;

        

        template <class T> using to_unsigned_t = typename to_unsigned<T>::type;

        

    }  // namespace internal

    

}  // namespace atcoder



#include <cassert>

#include <numeric>

#include <type_traits>



#ifdef _MSC_VER

#include <intrin.h>

#endif



namespace atcoder {

    

    namespace internal {

        

        struct modint_base {};

        struct static_modint_base : modint_base {};

        

        template <class T> using is_modint = std::is_base_of<modint_base, T>;

        template <class T> using is_modint_t = std::enable_if_t<is_modint<T>::value>;

        

    }  // namespace internal

    

    template <int m, std::enable_if_t<(1 <= m)>* = nullptr>

    struct static_modint : internal::static_modint_base {

        using mint = static_modint;

        

    public:

        static constexpr int mod() { return m; }

        static mint raw(int v) {

            mint x;

            x._v = v;

            return x;

        }

        

        static_modint() : _v(0) {}

        template <class T, internal::is_signed_int_t<T>* = nullptr>

        static_modint(T v) {

            long long x = (long long)(v % (long long)(umod()));

            if (x < 0) x += umod();

            _v = (unsigned int)(x);

        }

        template <class T, internal::is_unsigned_int_t<T>* = nullptr>

        static_modint(T v) {

            _v = (unsigned int)(v % umod());

        }

        static_modint(bool v) { _v = ((unsigned int)(v) % umod()); }

        

        unsigned int val() const { return _v; }

        

        mint& operator++() {

            _v++;

            if (_v == umod()) _v = 0;

            return *this;

        }

        mint& operator--() {

            if (_v == 0) _v = umod();

            _v--;

            return *this;

        }

        mint operator++(int) {

            mint result = *this;

            ++*this;

            return result;

        }

        mint operator--(int) {

            mint result = *this;

            --*this;

            return result;

        }

        

        mint& operator+=(const mint& rhs) {

            _v += rhs._v;

            if (_v >= umod()) _v -= umod();

            return *this;

        }

        mint& operator-=(const mint& rhs) {

            _v -= rhs._v;

            if (_v >= umod()) _v += umod();

            return *this;

        }

        mint& operator*=(const mint& rhs) {

            unsigned long long z = _v;

            z *= rhs._v;

            _v = (unsigned int)(z % umod());

            return *this;

        }

        mint& operator/=(const mint& rhs) { return *this = *this * rhs.inv(); }

        

        mint operator+() const { return *this; }

        mint operator-() const { return mint() - *this; }

        

        mint pow(long long n) const {

            assert(0 <= n);

            mint x = *this, r = 1;

            while (n) {

                if (n & 1) r *= x;

                x *= x;

                n >>= 1;

            }

            return r;

        }

        mint inv() const {

            if (prime) {

                assert(_v);

                return pow(umod() - 2);

            } else {

                auto eg = internal::inv_gcd(_v, m);

                assert(eg.first == 1);

                return eg.second;

            }

        }

        

        friend mint operator+(const mint& lhs, const mint& rhs) {

            return mint(lhs) += rhs;

        }

        friend mint operator-(const mint& lhs, const mint& rhs) {

            return mint(lhs) -= rhs;

        }

        friend mint operator*(const mint& lhs, const mint& rhs) {

            return mint(lhs) *= rhs;

        }

        friend mint operator/(const mint& lhs, const mint& rhs) {

            return mint(lhs) /= rhs;

        }

        friend bool operator==(const mint& lhs, const mint& rhs) {

            return lhs._v == rhs._v;

        }

        friend bool operator!=(const mint& lhs, const mint& rhs) {

            return lhs._v != rhs._v;

        }

        

    private:

        unsigned int _v;

        static constexpr unsigned int umod() { return m; }

        static constexpr bool prime = internal::is_prime<m>;

    };

    

    template <int id> struct dynamic_modint : internal::modint_base {

        using mint = dynamic_modint;

        

    public:

        static int mod() { return (int)(bt.umod()); }

        static void set_mod(int m) {

            assert(1 <= m);

            bt = internal::barrett(m);

        }

        static mint raw(int v) {

            mint x;

            x._v = v;

            return x;

        }

        

        dynamic_modint() : _v(0) {}

        template <class T, internal::is_signed_int_t<T>* = nullptr>

        dynamic_modint(T v) {

            long long x = (long long)(v % (long long)(mod()));

            if (x < 0) x += mod();

            _v = (unsigned int)(x);

        }

        template <class T, internal::is_unsigned_int_t<T>* = nullptr>

        dynamic_modint(T v) {

            _v = (unsigned int)(v % mod());

        }

        dynamic_modint(bool v) { _v = ((unsigned int)(v) % mod()); }

        

        unsigned int val() const { return _v; }

        

        mint& operator++() {

            _v++;

            if (_v == umod()) _v = 0;

            return *this;

        }

        mint& operator--() {

            if (_v == 0) _v = umod();

            _v--;

            return *this;

        }

        mint operator++(int) {

            mint result = *this;

            ++*this;

            return result;

        }

        mint operator--(int) {

            mint result = *this;

            --*this;

            return result;

        }

        

        mint& operator+=(const mint& rhs) {

            _v += rhs._v;

            if (_v >= umod()) _v -= umod();

            return *this;

        }

        mint& operator-=(const mint& rhs) {

            _v += mod() - rhs._v;

            if (_v >= umod()) _v -= umod();

            return *this;

        }

        mint& operator*=(const mint& rhs) {

            _v = bt.mul(_v, rhs._v);

            return *this;

        }

        mint& operator/=(const mint& rhs) { return *this = *this * rhs.inv(); }

        

        mint operator+() const { return *this; }

        mint operator-() const { return mint() - *this; }

        

        mint pow(long long n) const {

            assert(0 <= n);

            mint x = *this, r = 1;

            while (n) {

                if (n & 1) r *= x;

                x *= x;

                n >>= 1;

            }

            return r;

        }

        mint inv() const {

            auto eg = internal::inv_gcd(_v, mod());

            assert(eg.first == 1);

            return eg.second;

        }

        

        friend mint operator+(const mint& lhs, const mint& rhs) {

            return mint(lhs) += rhs;

        }

        friend mint operator-(const mint& lhs, const mint& rhs) {

            return mint(lhs) -= rhs;

        }

        friend mint operator*(const mint& lhs, const mint& rhs) {

            return mint(lhs) *= rhs;

        }

        friend mint operator/(const mint& lhs, const mint& rhs) {

            return mint(lhs) /= rhs;

        }

        friend bool operator==(const mint& lhs, const mint& rhs) {

            return lhs._v == rhs._v;

        }

        friend bool operator!=(const mint& lhs, const mint& rhs) {

            return lhs._v != rhs._v;

        }

        

    private:

        unsigned int _v;

        static internal::barrett bt;

        static unsigned int umod() { return bt.umod(); }

    };

    template <int id> internal::barrett dynamic_modint<id>::bt = 998244353;

    

    using modint998244353 = static_modint<998244353>;

    using modint1000000007 = static_modint<1000000007>;

    using modint = dynamic_modint<-1>;

    

    namespace internal {

        

        template <class T>

        using is_static_modint = std::is_base_of<internal::static_modint_base, T>;

        

        template <class T>

        using is_static_modint_t = std::enable_if_t<is_static_modint<T>::value>;

        

        template <class> struct is_dynamic_modint : public std::false_type {};

        template <int id>

        struct is_dynamic_modint<dynamic_modint<id>> : public std::true_type {};

        

        template <class T>

        using is_dynamic_modint_t = std::enable_if_t<is_dynamic_modint<T>::value>;

        

    }  // namespace internal

    

}  // namespace atcoder



#include <cassert>

#include <type_traits>

#include <vector>



namespace atcoder {

    

    namespace internal {

        

        template <class mint, internal::is_static_modint_t<mint>* = nullptr>

        void butterfly(std::vector<mint>& a) {

            static constexpr int g = internal::primitive_root<mint::mod()>;

            int n = int(a.size());

            int h = internal::ceil_pow2(n);

            

            static bool first = true;

            static mint sum_e[30];  // sum_e[i] = ies[0] * ... * ies[i - 1] * es[i]

            if (first) {

                first = false;

                mint es[30], ies[30];  // es[i]^(2^(2+i)) == 1

                int cnt2 = bsf(mint::mod() - 1);

                mint e = mint(g).pow((mint::mod() - 1) >> cnt2), ie = e.inv();

                for (int i = cnt2; i >= 2; i--) {

                    es[i - 2] = e;

                    ies[i - 2] = ie;

                    e *= e;

                    ie *= ie;

                }

                mint now = 1;

                for (int i = 0; i < cnt2 - 2; i++) {

                    sum_e[i] = es[i] * now;

                    now *= ies[i];

                }

            }

            for (int ph = 1; ph <= h; ph++) {

                int w = 1 << (ph - 1), p = 1 << (h - ph);

                mint now = 1;

                for (int s = 0; s < w; s++) {

                    int offset = s << (h - ph + 1);

                    for (int i = 0; i < p; i++) {

                        auto l = a[i + offset];

                        auto r = a[i + offset + p] * now;

                        a[i + offset] = l + r;

                        a[i + offset + p] = l - r;

                    }

                    now *= sum_e[bsf(~(unsigned int)(s))];

                }

            }

        }

        

        template <class mint, internal::is_static_modint_t<mint>* = nullptr>

        void butterfly_inv(std::vector<mint>& a) {

            static constexpr int g = internal::primitive_root<mint::mod()>;

            int n = int(a.size());

            int h = internal::ceil_pow2(n);

            

            static bool first = true;

            static mint sum_ie[30];  // sum_ie[i] = es[0] * ... * es[i - 1] * ies[i]

            if (first) {

                first = false;

                mint es[30], ies[30];  // es[i]^(2^(2+i)) == 1

                int cnt2 = bsf(mint::mod() - 1);

                mint e = mint(g).pow((mint::mod() - 1) >> cnt2), ie = e.inv();

                for (int i = cnt2; i >= 2; i--) {

                    es[i - 2] = e;

                    ies[i - 2] = ie;

                    e *= e;

                    ie *= ie;

                }

                mint now = 1;

                for (int i = 0; i < cnt2 - 2; i++) {

                    sum_ie[i] = ies[i] * now;

                    now *= es[i];

                }

            }

            

            for (int ph = h; ph >= 1; ph--) {

                int w = 1 << (ph - 1), p = 1 << (h - ph);

                mint inow = 1;

                for (int s = 0; s < w; s++) {

                    int offset = s << (h - ph + 1);

                    for (int i = 0; i < p; i++) {

                        auto l = a[i + offset];

                        auto r = a[i + offset + p];

                        a[i + offset] = l + r;

                        a[i + offset + p] =

                        (unsigned long long)(mint::mod() + l.val() - r.val()) *

                        inow.val();

                    }

                    inow *= sum_ie[bsf(~(unsigned int)(s))];

                }

            }

        }

        

    }  // namespace internal

    

    template <class mint, internal::is_static_modint_t<mint>* = nullptr>

    std::vector<mint> convolution(std::vector<mint> a, std::vector<mint> b) {

        int n = int(a.size()), m = int(b.size());

        if (!n || !m) return {};

        if (std::min(n, m) <= 60) {

            if (n < m) {

                std::swap(n, m);

                std::swap(a, b);

            }

            std::vector<mint> ans(n + m - 1);

            for (int i = 0; i < n; i++) {

                for (int j = 0; j < m; j++) {

                    ans[i + j] += a[i] * b[j];

                }

            }

            return ans;

        }

        int z = 1 << internal::ceil_pow2(n + m - 1);

        a.resize(z);

        internal::butterfly(a);

        b.resize(z);

        internal::butterfly(b);

        for (int i = 0; i < z; i++) {

            a[i] *= b[i];

        }

        internal::butterfly_inv(a);

        a.resize(n + m - 1);

        mint iz = mint(z).inv();

        for (int i = 0; i < n + m - 1; i++) a[i] *= iz;

        return a;

    }

    

    template <unsigned int mod = 998244353,

    class T,

    std::enable_if_t<internal::is_integral<T>::value>* = nullptr>

    std::vector<T> convolution(const std::vector<T>& a, const std::vector<T>& b) {

        int n = int(a.size()), m = int(b.size());

        if (!n || !m) return {};

        

        using mint = static_modint<mod>;

        std::vector<mint> a2(n), b2(m);

        for (int i = 0; i < n; i++) {

            a2[i] = mint(a[i]);

        }

        for (int i = 0; i < m; i++) {

            b2[i] = mint(b[i]);

        }

        auto c2 = convolution(move(a2), move(b2));

        std::vector<T> c(n + m - 1);

        for (int i = 0; i < n + m - 1; i++) {

            c[i] = c2[i].val();

        }

        return c;

    }

    

    std::vector<long long> convolution_ll(const std::vector<long long>& a,

                                          const std::vector<long long>& b) {

        int n = int(a.size()), m = int(b.size());

        if (!n || !m) return {};

        

        static constexpr unsigned long long MOD1 = 754974721;  // 2^24

        static constexpr unsigned long long MOD2 = 167772161;  // 2^25

        static constexpr unsigned long long MOD3 = 469762049;  // 2^26

        static constexpr unsigned long long M2M3 = MOD2 * MOD3;

        static constexpr unsigned long long M1M3 = MOD1 * MOD3;

        static constexpr unsigned long long M1M2 = MOD1 * MOD2;

        static constexpr unsigned long long M1M2M3 = MOD1 * MOD2 * MOD3;

        

        static constexpr unsigned long long i1 =

        internal::inv_gcd(MOD2 * MOD3, MOD1).second;

        static constexpr unsigned long long i2 =

        internal::inv_gcd(MOD1 * MOD3, MOD2).second;

        static constexpr unsigned long long i3 =

        internal::inv_gcd(MOD1 * MOD2, MOD3).second;

        

        auto c1 = convolution<MOD1>(a, b);

        auto c2 = convolution<MOD2>(a, b);

        auto c3 = convolution<MOD3>(a, b);

        

        std::vector<long long> c(n + m - 1);

        for (int i = 0; i < n + m - 1; i++) {

            unsigned long long x = 0;

            x += (c1[i] * i1) % MOD1 * M2M3;

            x += (c2[i] * i2) % MOD2 * M1M3;

            x += (c3[i] * i3) % MOD3 * M1M2;

            long long diff =

            c1[i] - internal::safe_mod((long long)(x), (long long)(MOD1));

            if (diff < 0) diff += MOD1;

            static constexpr unsigned long long offset[5] = {

                0, 0, M1M2M3, 2 * M1M2M3, 3 * M1M2M3};

            x -= offset[diff % 5];

            c[i] = x;

        }

        

        return c;

    }

    

}  // namespace atcoder





#include <algorithm>

#include <cassert>

#include <vector>



namespace atcoder {

    

    struct dsu {

    public:

        dsu() : _n(0) {}

        dsu(int n) : _n(n), parent_or_size(n, -1) {}

        

        int merge(int a, int b) {

            assert(0 <= a && a < _n);

            assert(0 <= b && b < _n);

            int x = leader(a), y = leader(b);

            if (x == y) return x;

            if (-parent_or_size[x] < -parent_or_size[y]) std::swap(x, y);

            parent_or_size[x] += parent_or_size[y];

            parent_or_size[y] = x;

            return x;

        }

        

        bool same(int a, int b) {

            assert(0 <= a && a < _n);

            assert(0 <= b && b < _n);

            return leader(a) == leader(b);

        }

        

        int leader(int a) {

            assert(0 <= a && a < _n);

            if (parent_or_size[a] < 0) return a;

            return parent_or_size[a] = leader(parent_or_size[a]);

        }

        

        int size(int a) {

            assert(0 <= a && a < _n);

            return -parent_or_size[leader(a)];

        }

        

        std::vector<std::vector<int>> groups() {

            std::vector<int> leader_buf(_n), group_size(_n);

            for (int i = 0; i < _n; i++) {

                leader_buf[i] = leader(i);

                group_size[leader_buf[i]]++;

            }

            std::vector<std::vector<int>> result(_n);

            for (int i = 0; i < _n; i++) {

                result[i].reserve(group_size[i]);

            }

            for (int i = 0; i < _n; i++) {

                result[leader_buf[i]].push_back(i);

            }

            result.erase(

                         std::remove_if(result.begin(), result.end(),

                                        [&](const std::vector<int>& v) { return v.empty(); }),

                         result.end());

            return result;

        }

        

    private:

        int _n;

        std::vector<int> parent_or_size;

    };

    

}  // namespace atcoder





#include <cassert>

#include <vector>



namespace atcoder {

    

    template <class T> struct fenwick_tree {

        using U = internal::to_unsigned_t<T>;

        

    public:

        fenwick_tree() : _n(0) {}

        fenwick_tree(int n) : _n(n), data(n) {}

        

        void add(int p, T x) {

            assert(0 <= p && p < _n);

            p++;

            while (p <= _n) {

                data[p - 1] += U(x);

                p += p & -p;

            }

        }

        

        T sum(int l, int r) {

            assert(0 <= l && l <= r && r <= _n);

            return sum(r) - sum(l);

        }

        

    private:

        int _n;

        std::vector<U> data;

        

        U sum(int r) {

            U s = 0;

            while (r > 0) {

                s += data[r - 1];

                r -= r & -r;

            }

            return s;

        }

    };

    

}  // namespace atcoder





#include <algorithm>

#include <cassert>

#include <iostream>

#include <vector>

namespace atcoder {

    

    template <class S,

    S (*op)(S, S),

    S (*e)(),

    class F,

    S (*mapping)(F, S),

    F (*composition)(F, F),

    F (*id)()>

    struct lazy_segtree {

    public:

        lazy_segtree() : lazy_segtree(0) {}

        lazy_segtree(int n) : lazy_segtree(std::vector<S>(n, e())) {}

        lazy_segtree(const std::vector<S>& v) : _n(int(v.size())) {

            log = internal::ceil_pow2(_n);

            size = 1 << log;

            d = std::vector<S>(2 * size, e());

            lz = std::vector<F>(size, id());

            for (int i = 0; i < _n; i++) d[size + i] = v[i];

            for (int i = size - 1; i >= 1; i--) {

                update(i);

            }

        }

        

        void set(int p, S x) {

            assert(0 <= p && p < _n);

            p += size;

            for (int i = log; i >= 1; i--) push(p >> i);

            d[p] = x;

            for (int i = 1; i <= log; i++) update(p >> i);

        }

        

        S get(int p) {

            assert(0 <= p && p < _n);

            p += size;

            for (int i = log; i >= 1; i--) push(p >> i);

            return d[p];

        }

        

        S prod(int l, int r) {

            assert(0 <= l && l <= r && r <= _n);

            if (l == r) return e();

            

            l += size;

            r += size;

            

            for (int i = log; i >= 1; i--) {

                if (((l >> i) << i) != l) push(l >> i);

                if (((r >> i) << i) != r) push(r >> i);

            }

            

            S sml = e(), smr = e();

            while (l < r) {

                if (l & 1) sml = op(sml, d[l++]);

                if (r & 1) smr = op(d[--r], smr);

                l >>= 1;

                r >>= 1;

            }

            

            return op(sml, smr);

        }

        

        S all_prod() { return d[1]; }

        

        void apply(int p, F f) {

            assert(0 <= p && p < _n);

            p += size;

            for (int i = log; i >= 1; i--) push(p >> i);

            d[p] = mapping(f, d[p]);

            for (int i = 1; i <= log; i++) update(p >> i);

        }

        void apply(int l, int r, F f) {

            assert(0 <= l && l <= r && r <= _n);

            if (l == r) return;

            

            l += size;

            r += size;

            

            for (int i = log; i >= 1; i--) {

                if (((l >> i) << i) != l) push(l >> i);

                if (((r >> i) << i) != r) push((r - 1) >> i);

            }

            

            {

                int l2 = l, r2 = r;

                while (l < r) {

                    if (l & 1) all_apply(l++, f);

                    if (r & 1) all_apply(--r, f);

                    l >>= 1;

                    r >>= 1;

                }

                l = l2;

                r = r2;

            }

            

            for (int i = 1; i <= log; i++) {

                if (((l >> i) << i) != l) update(l >> i);

                if (((r >> i) << i) != r) update((r - 1) >> i);

            }

        }

        

        template <bool (*g)(S)> int max_right(int l) {

            return max_right(l, [](S x) { return g(x); });

        }

        template <class G> int max_right(int l, G g) {

            assert(0 <= l && l <= _n);

            assert(g(e()));

            if (l == _n) return _n;

            l += size;

            for (int i = log; i >= 1; i--) push(l >> i);

            S sm = e();

            do {

                while (l % 2 == 0) l >>= 1;

                if (!g(op(sm, d[l]))) {

                    while (l < size) {

                        push(l);

                        l = (2 * l);

                        if (g(op(sm, d[l]))) {

                            sm = op(sm, d[l]);

                            l++;

                        }

                    }

                    return l - size;

                }

                sm = op(sm, d[l]);

                l++;

            } while ((l & -l) != l);

            return _n;

        }

        

        template <bool (*g)(S)> int min_left(int r) {

            return min_left(r, [](S x) { return g(x); });

        }

        template <class G> int min_left(int r, G g) {

            assert(0 <= r && r <= _n);

            assert(g(e()));

            if (r == 0) return 0;

            r += size;

            for (int i = log; i >= 1; i--) push((r - 1) >> i);

            S sm = e();

            do {

                r--;

                while (r > 1 && (r % 2)) r >>= 1;

                if (!g(op(d[r], sm))) {

                    while (r < size) {

                        push(r);

                        r = (2 * r + 1);

                        if (g(op(d[r], sm))) {

                            sm = op(d[r], sm);

                            r--;

                        }

                    }

                    return r + 1 - size;

                }

                sm = op(d[r], sm);

            } while ((r & -r) != r);

            return 0;

        }

        

    private:

        int _n, size, log;

        std::vector<S> d;

        std::vector<F> lz;

        

        void update(int k) { d[k] = op(d[2 * k], d[2 * k + 1]); }

        void all_apply(int k, F f) {

            d[k] = mapping(f, d[k]);

            if (k < size) lz[k] = composition(f, lz[k]);

        }

        void push(int k) {

            all_apply(2 * k, lz[k]);

            all_apply(2 * k + 1, lz[k]);

            lz[k] = id();

        }

    };

    

}  // namespace atcoder





#include <algorithm>

#include <cassert>

#include <tuple>

#include <vector>



namespace atcoder {

    

    long long pow_mod(long long x, long long n, int m) {

        assert(0 <= n && 1 <= m);

        if (m == 1) return 0;

        internal::barrett bt((unsigned int)(m));

        unsigned int r = 1, y = (unsigned int)(internal::safe_mod(x, m));

        while (n) {

            if (n & 1) r = bt.mul(r, y);

            y = bt.mul(y, y);

            n >>= 1;

        }

        return r;

    }

    

    long long inv_mod(long long x, long long m) {

        assert(1 <= m);

        auto z = internal::inv_gcd(x, m);

        assert(z.first == 1);

        return z.second;

    }

    

    std::pair<long long, long long> crt(const std::vector<long long>& r,

                                        const std::vector<long long>& m) {

        assert(r.size() == m.size());

        int n = int(r.size());

        long long r0 = 0, m0 = 1;

        for (int i = 0; i < n; i++) {

            assert(1 <= m[i]);

            long long r1 = internal::safe_mod(r[i], m[i]), m1 = m[i];

            if (m0 < m1) {

                std::swap(r0, r1);

                std::swap(m0, m1);

            }

            if (m0 % m1 == 0) {

                if (r0 % m1 != r1) return {0, 0};

                continue;

            }

            

            

            long long g, im;

            std::tie(g, im) = internal::inv_gcd(m0, m1);

            

            long long u1 = (m1 / g);

            if ((r1 - r0) % g) return {0, 0};

            

            long long x = (r1 - r0) / g % u1 * im % u1;

            

            r0 += x * m0;

            m0 *= u1;  // -> lcm(m0, m1)

            if (r0 < 0) r0 += m0;

        }

        return {r0, m0};

    }

    

    long long floor_sum(long long n, long long m, long long a, long long b) {

        long long ans = 0;

        if (a >= m) {

            ans += (n - 1) * n * (a / m) / 2;

            a %= m;

        }

        if (b >= m) {

            ans += n * (b / m);

            b %= m;

        }

        

        long long y_max = (a * n + b) / m, x_max = (y_max * m - b);

        if (y_max == 0) return ans;

        ans += (n - (x_max + a - 1) / a) * y_max;

        ans += floor_sum(y_max, a, m, (a - x_max % a) % a);

        return ans;

    }

    

}  // namespace atcoder





#include <algorithm>



#include <vector>



namespace atcoder {

    

    namespace internal {

        

        template <class T> struct simple_queue {

            std::vector<T> payload;

            int pos = 0;

            void reserve(int n) { payload.reserve(n); }

            int size() const { return int(payload.size()) - pos; }

            bool empty() const { return pos == int(payload.size()); }

            void push(const T& t) { payload.push_back(t); }

            T& front() { return payload[pos]; }

            void clear() {

                payload.clear();

                pos = 0;

            }

            void pop() { pos++; }

        };

        

    }  // namespace internal

    

}  // namespace atcoder



#include <cassert>

#include <limits>

#include <queue>

#include <vector>



namespace atcoder {

    

    template <class Cap> struct mf_graph {

    public:

        mf_graph() : _n(0) {}

        mf_graph(int n) : _n(n), g(n) {}

        

        int add_edge(int from, int to, Cap cap) {

            assert(0 <= from && from < _n);

            assert(0 <= to && to < _n);

            assert(0 <= cap);

            int m = int(pos.size());

            pos.push_back({from, int(g[from].size())});

            g[from].push_back(_edge{to, int(g[to].size()), cap});

            g[to].push_back(_edge{from, int(g[from].size()) - 1, 0});

            return m;

        }

        

        struct edge {

            int from, to;

            Cap cap, flow;

        };

        

        edge get_edge(int i) {

            int m = int(pos.size());

            assert(0 <= i && i < m);

            auto _e = g[pos[i].first][pos[i].second];

            auto _re = g[_e.to][_e.rev];

            return edge{pos[i].first, _e.to, _e.cap + _re.cap, _re.cap};

        }

        std::vector<edge> edges() {

            int m = int(pos.size());

            std::vector<edge> result;

            for (int i = 0; i < m; i++) {

                result.push_back(get_edge(i));

            }

            return result;

        }

        void change_edge(int i, Cap new_cap, Cap new_flow) {

            int m = int(pos.size());

            assert(0 <= i && i < m);

            assert(0 <= new_flow && new_flow <= new_cap);

            auto& _e = g[pos[i].first][pos[i].second];

            auto& _re = g[_e.to][_e.rev];

            _e.cap = new_cap - new_flow;

            _re.cap = new_flow;

        }

        

        Cap flow(int s, int t) {

            return flow(s, t, std::numeric_limits<Cap>::max());

        }

        Cap flow(int s, int t, Cap flow_limit) {

            assert(0 <= s && s < _n);

            assert(0 <= t && t < _n);

            

            std::vector<int> level(_n), iter(_n);

            internal::simple_queue<int> que;

            

            auto bfs = [&]() {

                std::fill(level.begin(), level.end(), -1);

                level[s] = 0;

                que.clear();

                que.push(s);

                while (!que.empty()) {

                    int v = que.front();

                    que.pop();

                    for (auto e : g[v]) {

                        if (e.cap == 0 || level[e.to] >= 0) continue;

                        level[e.to] = level[v] + 1;

                        if (e.to == t) return;

                        que.push(e.to);

                    }

                }

            };

            auto dfs = [&](auto self, int v, Cap up) {

                if (v == s) return up;

                Cap res = 0;

                int level_v = level[v];

                for (int& i = iter[v]; i < int(g[v].size()); i++) {

                    _edge& e = g[v][i];

                    if (level_v <= level[e.to] || g[e.to][e.rev].cap == 0) continue;

                    Cap d =

                    self(self, e.to, std::min(up - res, g[e.to][e.rev].cap));

                    if (d <= 0) continue;

                    g[v][i].cap += d;

                    g[e.to][e.rev].cap -= d;

                    res += d;

                    if (res == up) break;

                }

                return res;

            };

            

            Cap flow = 0;

            while (flow < flow_limit) {

                bfs();

                if (level[t] == -1) break;

                std::fill(iter.begin(), iter.end(), 0);

                while (flow < flow_limit) {

                    Cap f = dfs(dfs, t, flow_limit - flow);

                    if (!f) break;

                    flow += f;

                }

            }

            return flow;

        }

        

        std::vector<bool> min_cut(int s) {

            std::vector<bool> visited(_n);

            internal::simple_queue<int> que;

            que.push(s);

            while (!que.empty()) {

                int p = que.front();

                que.pop();

                visited[p] = true;

                for (auto e : g[p]) {

                    if (e.cap && !visited[e.to]) {

                        visited[e.to] = true;

                        que.push(e.to);

                    }

                }

            }

            return visited;

        }

        

    private:

        int _n;

        struct _edge {

            int to, rev;

            Cap cap;

        };

        std::vector<std::pair<int, int>> pos;

        std::vector<std::vector<_edge>> g;

    };

    

}  // namespace atcoder





#include <algorithm>

#include <cassert>

#include <limits>

#include <queue>

#include <vector>



namespace atcoder {

    

    template <class Cap, class Cost> struct mcf_graph {

    public:

        mcf_graph() {}

        mcf_graph(int n) : _n(n), g(n) {}

        

        int add_edge(int from, int to, Cap cap, Cost cost) {

            assert(0 <= from && from < _n);

            assert(0 <= to && to < _n);

            int m = int(pos.size());

            pos.push_back({from, int(g[from].size())});

            g[from].push_back(_edge{to, int(g[to].size()), cap, cost});

            g[to].push_back(_edge{from, int(g[from].size()) - 1, 0, -cost});

            return m;

        }

        

        struct edge {

            int from, to;

            Cap cap, flow;

            Cost cost;

        };

        

        edge get_edge(int i) {

            int m = int(pos.size());

            assert(0 <= i && i < m);

            auto _e = g[pos[i].first][pos[i].second];

            auto _re = g[_e.to][_e.rev];

            return edge{

                pos[i].first, _e.to, _e.cap + _re.cap, _re.cap, _e.cost,

            };

        }

        std::vector<edge> edges() {

            int m = int(pos.size());

            std::vector<edge> result(m);

            for (int i = 0; i < m; i++) {

                result[i] = get_edge(i);

            }

            return result;

        }

        

        std::pair<Cap, Cost> flow(int s, int t) {

            return flow(s, t, std::numeric_limits<Cap>::max());

        }

        std::pair<Cap, Cost> flow(int s, int t, Cap flow_limit) {

            return slope(s, t, flow_limit).back();

        }

        std::vector<std::pair<Cap, Cost>> slope(int s, int t) {

            return slope(s, t, std::numeric_limits<Cap>::max());

        }

        std::vector<std::pair<Cap, Cost>> slope(int s, int t, Cap flow_limit) {

            assert(0 <= s && s < _n);

            assert(0 <= t && t < _n);

            assert(s != t);

            std::vector<Cost> dual(_n, 0), dist(_n);

            std::vector<int> pv(_n), pe(_n);

            std::vector<bool> vis(_n);

            auto dual_ref = [&]() {

                std::fill(dist.begin(), dist.end(),

                          std::numeric_limits<Cost>::max());

                std::fill(pv.begin(), pv.end(), -1);

                std::fill(pe.begin(), pe.end(), -1);

                std::fill(vis.begin(), vis.end(), false);

                struct Q {

                    Cost key;

                    int to;

                    bool operator<(Q r) const { return key > r.key; }

                };

                std::priority_queue<Q> que;

                dist[s] = 0;

                que.push(Q{0, s});

                while (!que.empty()) {

                    int v = que.top().to;

                    que.pop();

                    if (vis[v]) continue;

                    vis[v] = true;

                    if (v == t) break;

                    for (int i = 0; i < int(g[v].size()); i++) {

                        auto e = g[v][i];

                        if (vis[e.to] || !e.cap) continue;

                        Cost cost = e.cost - dual[e.to] + dual[v];

                        if (dist[e.to] - dist[v] > cost) {

                            dist[e.to] = dist[v] + cost;

                            pv[e.to] = v;

                            pe[e.to] = i;

                            que.push(Q{dist[e.to], e.to});

                        }

                    }

                }

                if (!vis[t]) {

                    return false;

                }

                

                for (int v = 0; v < _n; v++) {

                    if (!vis[v]) continue;

                    dual[v] -= dist[t] - dist[v];

                }

                return true;

            };

            Cap flow = 0;

            Cost cost = 0, prev_cost = -1;

            std::vector<std::pair<Cap, Cost>> result;

            result.push_back({flow, cost});

            while (flow < flow_limit) {

                if (!dual_ref()) break;

                Cap c = flow_limit - flow;

                for (int v = t; v != s; v = pv[v]) {

                    c = std::min(c, g[pv[v]][pe[v]].cap);

                }

                for (int v = t; v != s; v = pv[v]) {

                    auto& e = g[pv[v]][pe[v]];

                    e.cap -= c;

                    g[v][e.rev].cap += c;

                }

                Cost d = -dual[s];

                flow += c;

                cost += c * d;

                if (prev_cost == d) {

                    result.pop_back();

                }

                result.push_back({flow, cost});

                prev_cost = cost;

            }

            return result;

        }

        

    private:

        int _n;

        

        struct _edge {

            int to, rev;

            Cap cap;

            Cost cost;

        };

        

        std::vector<std::pair<int, int>> pos;

        std::vector<std::vector<_edge>> g;

    };

    

}  // namespace atcoder





#include <algorithm>



#include <algorithm>

#include <utility>

#include <vector>



namespace atcoder {

    namespace internal {

        

        template <class E> struct csr {

            std::vector<int> start;

            std::vector<E> elist;

            csr(int n, const std::vector<std::pair<int, E>>& edges)

            : start(n + 1), elist(edges.size()) {

                for (auto e : edges) {

                    start[e.first + 1]++;

                }

                for (int i = 1; i <= n; i++) {

                    start[i] += start[i - 1];

                }

                auto counter = start;

                for (auto e : edges) {

                    elist[counter[e.first]++] = e.second;

                }

            }

        };

        

        struct scc_graph {

        public:

            scc_graph(int n) : _n(n) {}

            

            int num_vertices() { return _n; }

            

            void add_edge(int from, int to) { edges.push_back({from, {to}}); }

            

            std::pair<int, std::vector<int>> scc_ids() {

                auto g = csr<edge>(_n, edges);

                int now_ord = 0, group_num = 0;

                std::vector<int> visited, low(_n), ord(_n, -1), ids(_n);

                visited.reserve(_n);

                auto dfs = [&](auto self, int v) -> void {

                    low[v] = ord[v] = now_ord++;

                    visited.push_back(v);

                    for (int i = g.start[v]; i < g.start[v + 1]; i++) {

                        auto to = g.elist[i].to;

                        if (ord[to] == -1) {

                            self(self, to);

                            low[v] = std::min(low[v], low[to]);

                        } else {

                            low[v] = std::min(low[v], ord[to]);

                        }

                    }

                    if (low[v] == ord[v]) {

                        while (true) {

                            int u = visited.back();

                            visited.pop_back();

                            ord[u] = _n;

                            ids[u] = group_num;

                            if (u == v) break;

                        }

                        group_num++;

                    }

                };

                for (int i = 0; i < _n; i++) {

                    if (ord[i] == -1) dfs(dfs, i);

                }

                for (auto& x : ids) {

                    x = group_num - 1 - x;

                }

                return {group_num, ids};

            }

            

            std::vector<std::vector<int>> scc() {

                auto ids = scc_ids();

                int group_num = ids.first;

                std::vector<int> counts(group_num);

                for (auto x : ids.second) counts[x]++;

                std::vector<std::vector<int>> groups(ids.first);

                for (int i = 0; i < group_num; i++) {

                    groups[i].reserve(counts[i]);

                }

                for (int i = 0; i < _n; i++) {

                    groups[ids.second[i]].push_back(i);

                }

                return groups;

            }

            

        private:

            int _n;

            struct edge {

                int to;

            };

            std::vector<std::pair<int, edge>> edges;

        };

        

    }  // namespace internal

    

}  // namespace atcoder



#include <cassert>

#include <vector>



namespace atcoder {

    

    struct scc_graph {

    public:

        scc_graph() : internal(0) {}

        scc_graph(int n) : internal(n) {}

        

        void add_edge(int from, int to) {

            int n = internal.num_vertices();

            assert(0 <= from && from < n);

            assert(0 <= to && to < n);

            internal.add_edge(from, to);

        }

        

        std::vector<std::vector<int>> scc() { return internal.scc(); }

        

    private:

        internal::scc_graph internal;

    };

    

}  // namespace atcoder





#include <algorithm>

#include <cassert>

#include <vector>



namespace atcoder {

    

    template <class S, S (*op)(S, S), S (*e)()> struct segtree {

    public:

        segtree() : segtree(0) {}

        segtree(int n) : segtree(std::vector<S>(n, e())) {}

        segtree(const std::vector<S>& v) : _n(int(v.size())) {

            log = internal::ceil_pow2(_n);

            size = 1 << log;

            d = std::vector<S>(2 * size, e());

            for (int i = 0; i < _n; i++) d[size + i] = v[i];

            for (int i = size - 1; i >= 1; i--) {

                update(i);

            }

        }

        

        void set(int p, S x) {

            assert(0 <= p && p < _n);

            p += size;

            d[p] = x;

            for (int i = 1; i <= log; i++) update(p >> i);

        }

        

        S get(int p) {

            assert(0 <= p && p < _n);

            return d[p + size];

        }

        

        S prod(int l, int r) {

            assert(0 <= l && l <= r && r <= _n);

            S sml = e(), smr = e();

            l += size;

            r += size;

            

            while (l < r) {

                if (l & 1) sml = op(sml, d[l++]);

                if (r & 1) smr = op(d[--r], smr);

                l >>= 1;

                r >>= 1;

            }

            return op(sml, smr);

        }

        

        S all_prod() { return d[1]; }

        

        template <bool (*f)(S)> int max_right(int l) {

            return max_right(l, [](S x) { return f(x); });

        }

        template <class F> int max_right(int l, F f) {

            assert(0 <= l && l <= _n);

            assert(f(e()));

            if (l == _n) return _n;

            l += size;

            S sm = e();

            do {

                while (l % 2 == 0) l >>= 1;

                if (!f(op(sm, d[l]))) {

                    while (l < size) {

                        l = (2 * l);

                        if (f(op(sm, d[l]))) {

                            sm = op(sm, d[l]);

                            l++;

                        }

                    }

                    return l - size;

                }

                sm = op(sm, d[l]);

                l++;

            } while ((l & -l) != l);

            return _n;

        }

        

        template <bool (*f)(S)> int min_left(int r) {

            return min_left(r, [](S x) { return f(x); });

        }

        template <class F> int min_left(int r, F f) {

            assert(0 <= r && r <= _n);

            assert(f(e()));

            if (r == 0) return 0;

            r += size;

            S sm = e();

            do {

                r--;

                while (r > 1 && (r % 2)) r >>= 1;

                if (!f(op(d[r], sm))) {

                    while (r < size) {

                        r = (2 * r + 1);

                        if (f(op(d[r], sm))) {

                            sm = op(d[r], sm);

                            r--;

                        }

                    }

                    return r + 1 - size;

                }

                sm = op(d[r], sm);

            } while ((r & -r) != r);

            return 0;

        }

        

    private:

        int _n, size, log;

        std::vector<S> d;

        

        void update(int k) { d[k] = op(d[2 * k], d[2 * k + 1]); }

    };

    

}  // namespace atcoder





#include <algorithm>

#include <cassert>

#include <numeric>

#include <string>

#include <vector>



namespace atcoder {

    

    namespace internal {

        

        std::vector<int> sa_naive(const std::vector<int>& s) {

            int n = int(s.size());

            std::vector<int> sa(n);

            std::iota(sa.begin(), sa.end(), 0);

            std::sort(sa.begin(), sa.end(), [&](int l, int r) {

                if (l == r) return false;

                while (l < n && r < n) {

                    if (s[l] != s[r]) return s[l] < s[r];

                    l++;

                    r++;

                }

                return l == n;

            });

            return sa;

        }

        

        std::vector<int> sa_doubling(const std::vector<int>& s) {

            int n = int(s.size());

            std::vector<int> sa(n), rnk = s, tmp(n);

            std::iota(sa.begin(), sa.end(), 0);

            for (int k = 1; k < n; k *= 2) {

                auto cmp = [&](int x, int y) {

                    if (rnk[x] != rnk[y]) return rnk[x] < rnk[y];

                    int rx = x + k < n ? rnk[x + k] : -1;

                    int ry = y + k < n ? rnk[y + k] : -1;

                    return rx < ry;

                };

                std::sort(sa.begin(), sa.end(), cmp);

                tmp[sa[0]] = 0;

                for (int i = 1; i < n; i++) {

                    tmp[sa[i]] = tmp[sa[i - 1]] + (cmp(sa[i - 1], sa[i]) ? 1 : 0);

                }

                std::swap(tmp, rnk);

            }

            return sa;

        }

        

        template <int THRESHOLD_NAIVE = 10, int THRESHOLD_DOUBLING = 40>

        std::vector<int> sa_is(const std::vector<int>& s, int upper) {

            int n = int(s.size());

            if (n == 0) return {};

            if (n == 1) return {0};

            if (n == 2) {

                if (s[0] < s[1]) {

                    return {0, 1};

                } else {

                    return {1, 0};

                }

            }

            if (n < THRESHOLD_NAIVE) {

                return sa_naive(s);

            }

            if (n < THRESHOLD_DOUBLING) {

                return sa_doubling(s);

            }

            

            std::vector<int> sa(n);

            std::vector<bool> ls(n);

            for (int i = n - 2; i >= 0; i--) {

                ls[i] = (s[i] == s[i + 1]) ? ls[i + 1] : (s[i] < s[i + 1]);

            }

            std::vector<int> sum_l(upper + 1), sum_s(upper + 1);

            for (int i = 0; i < n; i++) {

                if (!ls[i]) {

                    sum_s[s[i]]++;

                } else {

                    sum_l[s[i] + 1]++;

                }

            }

            for (int i = 0; i <= upper; i++) {

                sum_s[i] += sum_l[i];

                if (i < upper) sum_l[i + 1] += sum_s[i];

            }

            

            auto induce = [&](const std::vector<int>& lms) {

                std::fill(sa.begin(), sa.end(), -1);

                std::vector<int> buf(upper + 1);

                std::copy(sum_s.begin(), sum_s.end(), buf.begin());

                for (auto d : lms) {

                    if (d == n) continue;

                    sa[buf[s[d]]++] = d;

                }

                std::copy(sum_l.begin(), sum_l.end(), buf.begin());

                sa[buf[s[n - 1]]++] = n - 1;

                for (int i = 0; i < n; i++) {

                    int v = sa[i];

                    if (v >= 1 && !ls[v - 1]) {

                        sa[buf[s[v - 1]]++] = v - 1;

                    }

                }

                std::copy(sum_l.begin(), sum_l.end(), buf.begin());

                for (int i = n - 1; i >= 0; i--) {

                    int v = sa[i];

                    if (v >= 1 && ls[v - 1]) {

                        sa[--buf[s[v - 1] + 1]] = v - 1;

                    }

                }

            };

            

            std::vector<int> lms_map(n + 1, -1);

            int m = 0;

            for (int i = 1; i < n; i++) {

                if (!ls[i - 1] && ls[i]) {

                    lms_map[i] = m++;

                }

            }

            std::vector<int> lms;

            lms.reserve(m);

            for (int i = 1; i < n; i++) {

                if (!ls[i - 1] && ls[i]) {

                    lms.push_back(i);

                }

            }

            

            induce(lms);

            

            if (m) {

                std::vector<int> sorted_lms;

                sorted_lms.reserve(m);

                for (int v : sa) {

                    if (lms_map[v] != -1) sorted_lms.push_back(v);

                }

                std::vector<int> rec_s(m);

                int rec_upper = 0;

                rec_s[lms_map[sorted_lms[0]]] = 0;

                for (int i = 1; i < m; i++) {

                    int l = sorted_lms[i - 1], r = sorted_lms[i];

                    int end_l = (lms_map[l] + 1 < m) ? lms[lms_map[l] + 1] : n;

                    int end_r = (lms_map[r] + 1 < m) ? lms[lms_map[r] + 1] : n;

                    bool same = true;

                    if (end_l - l != end_r - r) {

                        same = false;

                    } else {

                        while (l < end_l) {

                            if (s[l] != s[r]) {

                                break;

                            }

                            l++;

                            r++;

                        }

                        if (l == n || s[l] != s[r]) same = false;

                    }

                    if (!same) rec_upper++;

                    rec_s[lms_map[sorted_lms[i]]] = rec_upper;

                }

                

                auto rec_sa =

                sa_is<THRESHOLD_NAIVE, THRESHOLD_DOUBLING>(rec_s, rec_upper);

                

                for (int i = 0; i < m; i++) {

                    sorted_lms[i] = lms[rec_sa[i]];

                }

                induce(sorted_lms);

            }

            return sa;

        }

        

    }  // namespace internal

    

    std::vector<int> suffix_array(const std::vector<int>& s, int upper) {

        assert(0 <= upper);

        for (int d : s) {

            assert(0 <= d && d <= upper);

        }

        auto sa = internal::sa_is(s, upper);

        return sa;

    }

    

    template <class T> std::vector<int> suffix_array(const std::vector<T>& s) {

        int n = int(s.size());

        std::vector<int> idx(n);

        iota(idx.begin(), idx.end(), 0);

        sort(idx.begin(), idx.end(), [&](int l, int r) { return s[l] < s[r]; });

        std::vector<int> s2(n);

        int now = 0;

        for (int i = 0; i < n; i++) {

            if (i && s[idx[i - 1]] != s[idx[i]]) now++;

            s2[idx[i]] = now;

        }

        return internal::sa_is(s2, now);

    }

    

    std::vector<int> suffix_array(const std::string& s) {

        int n = int(s.size());

        std::vector<int> s2(n);

        for (int i = 0; i < n; i++) {

            s2[i] = s[i];

        }

        return internal::sa_is(s2, 255);

    }

    

    template <class T>

    std::vector<int> lcp_array(const std::vector<T>& s,

                               const std::vector<int>& sa) {

        int n = int(s.size());

        assert(n >= 1);

        std::vector<int> rnk(n);

        for (int i = 0; i < n; i++) {

            rnk[sa[i]] = i;

        }

        std::vector<int> lcp(n - 1);

        int h = 0;

        for (int i = 0; i < n; i++) {

            if (h > 0) h--;

            if (rnk[i] == 0) continue;

            int j = sa[rnk[i] - 1];

            for (; j + h < n && i + h < n; h++) {

                if (s[j + h] != s[i + h]) break;

            }

            lcp[rnk[i] - 1] = h;

        }

        return lcp;

    }

    

    std::vector<int> lcp_array(const std::string& s, const std::vector<int>& sa) {

        int n = int(s.size());

        std::vector<int> s2(n);

        for (int i = 0; i < n; i++) {

            s2[i] = s[i];

        }

        return lcp_array(s2, sa);

    }

    

    template <class T> std::vector<int> z_algorithm(const std::vector<T>& s) {

        int n = int(s.size());

        if (n == 0) return {};

        std::vector<int> z(n);

        z[0] = 0;

        for (int i = 1, j = 0; i < n; i++) {

            int& k = z[i];

            k = (j + z[j] <= i) ? 0 : std::min(j + z[j] - i, z[i - j]);

            while (i + k < n && s[k] == s[i + k]) k++;

            if (j + z[j] < i + z[i]) j = i;

        }

        z[0] = n;

        return z;

    }

    

    std::vector<int> z_algorithm(const std::string& s) {

        int n = int(s.size());

        std::vector<int> s2(n);

        for (int i = 0; i < n; i++) {

            s2[i] = s[i];

        }

        return z_algorithm(s2);

    }

    

}  // namespace atcoder





#include <cassert>

#include <vector>



namespace atcoder {

    

    struct two_sat {

    public:

        two_sat() : _n(0), scc(0) {}

        two_sat(int n) : _n(n), _answer(n), scc(2 * n) {}

        

        void add_clause(int i, bool f, int j, bool g) {

            assert(0 <= i && i < _n);

            assert(0 <= j && j < _n);

            scc.add_edge(2 * i + (f ? 0 : 1), 2 * j + (g ? 1 : 0));

            scc.add_edge(2 * j + (g ? 0 : 1), 2 * i + (f ? 1 : 0));

        }

        bool satisfiable() {

            auto id = scc.scc_ids().second;

            for (int i = 0; i < _n; i++) {

                if (id[2 * i] == id[2 * i + 1]) return false;

                _answer[i] = id[2 * i] < id[2 * i + 1];

            }

            return true;

        }

        std::vector<bool> answer() { return _answer; }

        

    private:

        int _n;

        std::vector<bool> _answer;

        internal::scc_graph scc;

    };

    

}  // namespace atcoder



const int mod=1000000007,MAX=2005,INF=1<<30;



using mint=atcoder::modint1000000007;



mint inv[MAX],fac[MAX],finv[MAX];



void make(){

    

    fac[0]=fac[1]=1;

    finv[0]=finv[1]=1;

    inv[1]=1;

    

    for(int i=2;i<MAX;i++){

        inv[i]=-inv[mod%i]*(mod/i);

        fac[i]=fac[i-1]*i;

        finv[i]=finv[i-1]*inv[i];

    }

}



mint comb(ll a,ll b){

    if(a<b) return 0;

    return fac[a]*finv[b]*finv[a-b];

}



mint perm(ll a,ll b){

    if(a<b) return 0;

    return fac[a]*finv[a-b];

}



int main(){

    

    std::ifstream in("text.txt");

    std::cin.rdbuf(in.rdbuf());

    cin.tie(0);

    ios::sync_with_stdio(false);

    

    int S;cin>>S;

    make();

    

    mint ans=0;

    

    for(int i=1;i<=S/3;i++){

        ans+=comb(S-i*3+i-1,i-1);

    }

    

    cout<<ans.val()<<endl;

}