//                              ______  ______  ______
// .-----..-----..-----..-----.|    __||__    ||  __  |
// |     ||  _  ||     ||  _  ||  __  ||    __||  __  |
// |__|__||___  ||__|__||___  ||______||______||______|
//        |_____|       |_____|
//
# include <bits/stdc++.h>
# define rep(i,n) for(int i=0, i##_len=(n); i<i##_len; ++i)
# define rep2(x,y,w,h) rep (x, w) rep (y, h)
# define reps(i,n) for(int i=1, i##_len=(n); i<=i##_len; ++i)
# define reps2(x,y,w,h) reps (x, w) reps (y, h)
# define rrep(i,n) for(int i=((int)(n)-1); i>=0; --i)
# define rreps(i,n) for(int i=((int)(n)); i>0; --i)
# define repr(i,b,e) for(int i=(b), i##_len=(e); i<i##_len; ++i)
# define reprs(i,b,e) for(int i=(b), i##_len=(e); i<i##_len; ++i)
# define step(n) rep(_, n)
# define ALL(x) (x).begin(), (x).end()
# define RALL(x) (x).rbegin(), (x).rend()
# define pb push_back
# define eb emplace_back
# define len(x) ((int)(x).size())
# define contains(x,key) ((x).find(key) != (x).end())
# define cauto const auto
# define int long long
# define float long double
# define FI first
# define SE second
using namespace std;
using vi = vector<int>;
using vb = vector<bool>;
using vvi = vector<vector<int>>;
using vs = vector<string>;
using pii = pair<int, int>;
using vpii = vector<pair<int, int>>;
using mii = map<int, int>;
using msi = map<string, int>;
template <class Type> inline constexpr Type Square(Type x) { return x * x; }
template <class Type> inline constexpr bool InRange(const Type& x, const Type& fst, const Type& lst) { return (fst <= x) && (x < lst); }
template <class Type> inline void Unique(Type& v) { sort(v.begin(), v.end()); v.erase(unique(v.begin(), v.end()), v.end()); }
template<class Integer> inline constexpr bool chmax(Integer &a, Integer b) { return a < b && (a = b, true); }
template<class Integer> inline constexpr bool chmin(Integer &a, Integer b) { return a > b && (a = b, true); }
template<class Integer>bool constexpr IsOdd(Integer &n) { return n & 1; }
template<class Integer>bool constexpr IsEven(Integer &n) { return !(n & 1); }
constexpr long long gcd(long long a, long long b) { while(b){ long long A = a; (a = b), (b = A % b); } return a; }
constexpr long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }
constexpr int ctoi(const char c) { return ('0' <= c && c <= '9') ? (c - '0') : -1; }
string YesNo(bool b) { return b ? "Yes" : "No"; }
string YESNO(bool b) { return b ? "YES" : "NO"; }
string yesno(bool b) { return b ? "yes" : "no"; }
void _cin(){} template <class Head, class... Tail> void _cin(Head&& head, Tail&&... tail){ cin >> head; _cin(forward<Tail>(tail)...); }
# define Cin(Type, ...) Type __VA_ARGS__; _cin(__VA_ARGS__)
# define Cinv(Type, xs, n) vector<Type> xs(n); rep(i, n) cin >> xs[i]
# define Cinv2(Type, xs, ys, n) vector<Type> xs(n), ys(n); rep(i, n) cin >> xs[i] >> ys[i]
# define Cinv3(Type, xs, ys, zs, n) vector<Type> xs(n), ys(n), zs(n); rep(i, n) cin >> xs[i] >> ys[i] >> zs[i]
# define Cinvv(Type, xs, h, w) vector<vector<Type>> xs(h, vector<int>(w)); rep(i, h) rep(j, w) cin >> xs[i][j]
void Print() { cout << endl; }
template <class Head, class... Tail> void Print(Head&& head, Tail&&... tail) { cout << head; if (sizeof...(tail) != 0) cout << " "; Print(forward<Tail>(tail)...); }
template <class Type> void Print(vector<Type> &vec) { for (auto& a : vec) { cout << a; if (&a != &vec.back()) cout << " "; } cout << endl; }
template <class Type> void Print(vector<vector<Type>> &df) { for (auto& vec : df) { Print(vec); } }
void Debug() { cerr << endl; }
template <class Head, class... Tail> void Debug(Head&& head, Tail&&... tail) { cerr << head; if (sizeof...(tail) != 0) cerr << " "; Debug(forward<Tail>(tail)...); }
template <class Type> void Debug(vector<Type> &vec) { for (auto& a : vec) { cerr << a; if (&a != &vec.back()) cerr << " "; } cerr << endl; }
template <class Type> void Debug(vector<vector<Type>> &df) { for (auto& vec : df) { Debug(vec); } }

template<int MOD> struct Fp {
    long long val;
    constexpr Fp(long long v = 0) noexcept : val(v % MOD) { if (val < 0) val += MOD; }
    constexpr int getmod() { return MOD; }
    constexpr Fp operator - () const noexcept { return val ? MOD - val : 0; }
    constexpr Fp operator + (const Fp& r) const noexcept { return Fp(*this) += r; }
    constexpr Fp operator - (const Fp& r) const noexcept { return Fp(*this) -= r; }
    constexpr Fp operator * (const Fp& r) const noexcept { return Fp(*this) *= r; }
    constexpr Fp operator / (const Fp& r) const noexcept { return Fp(*this) /= r; }
    constexpr Fp& operator += (const Fp& r) noexcept {
        val += r.val;
        if (val >= MOD) val -= MOD;
        return *this;
    }
    constexpr Fp& operator -= (const Fp& r) noexcept {
        val -= r.val;
        if (val < 0) val += MOD;
        return *this;
    }
    constexpr Fp& operator *= (const Fp& r) noexcept {
        val = val * r.val % MOD;
        return *this;
    }
    constexpr Fp& operator /= (const Fp& r) noexcept {
        long long a = r.val, b = MOD, u = 1, v = 0;
        while (b) {
            long long t = a / b;
            a -= t * b; swap(a, b);
            u -= t * v; swap(u, v);
        }
        val = val * u % MOD;
        if (val < 0) val += MOD;
        return *this;
    }
    constexpr bool operator == (const Fp& r) const noexcept { return this->val == r.val; }
    constexpr bool operator != (const Fp& r) const noexcept { return this->val != r.val; }
    friend constexpr Fp<MOD> modpow(const Fp<MOD> &a, long long n) noexcept {
        if (n == 0) return 1;
        auto t = modpow(a, n / 2);
        t = t * t;
        if (n & 1) t = t * a;
        return t;
    }
    friend constexpr ostream& operator << (ostream &os, const Fp<MOD>& x) noexcept { return os << x.val; }
    friend constexpr istream& operator >> (istream &is, Fp<MOD>& x) noexcept {
        istream& ret = is >> x.val;
        x.val %= MOD;
        return ret;
    }
};

static const int MOD = 1000000007;
using mint = Fp<MOD>;

static const int S_MAX = 2000;
mint dp[S_MAX + 1];

signed main()
{
    Cin(int, S);
    
    dp[0] = 1;
    dp[1] = 0;
    dp[2] = 0;
    reps (i, S_MAX) {
        for (int k = 3; i - k >= 0; ++k) {
            dp[i] += dp[i-k];
        }
    }

    Print(dp[S]);

    return 0;
}


Measured memory_bytes: 3624