#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
typedef pair<long long, long long> P;
#define override_rep(i, l, r, mes, ...) mes
#define rep1(i, n) for (int i = 0; i < n; i++)
#define rep2(i, l, r) for (int i = l; i < r; i++)
#define rep(...) override_rep(__VA_ARGS__, rep2, rep1)(__VA_ARGS__)
#ifdef DEBUG
std::ostream& dout = cout;
#else
stringstream dout;
#endif
template<typename T, typename U>
istream& operator>>(istream& in, pair<T, U>& p) {
    in >> p.first >> p.second;
    return in;
}
int digit(int n,int k){
    int ret=1,cnt=1;
    while(1){
        if(n<=cnt*k-1){
            return ret;
        }
        ret++;
        cnt*=k;
    }
}
template< int mod >
struct ModInt {
    int x;

    ModInt() : x(0) {}

    ModInt(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}

    ModInt &operator+=(const ModInt &p) {
        if((x += p.x) >= mod) x -= mod;
        return *this;
    }

    ModInt &operator-=(const ModInt &p) {
        if((x += mod - p.x) >= mod) x -= mod;
        return *this;
    }

    ModInt &operator*=(const ModInt &p) {
        x = (int) (1LL * x * p.x % mod);
        return *this;
    }

    ModInt &operator/=(const ModInt &p) {
        *this *= p.inverse();
        return *this;
    }

    ModInt operator-() const { return ModInt(-x); }

    ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }

    ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }

    ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }

    ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }

    bool operator==(const ModInt &p) const { return x == p.x; }

    bool operator!=(const ModInt &p) const { return x != p.x; }

    ModInt inverse() const {
        int a = x, b = mod, u = 1, v = 0, t;
        while(b > 0) {
            t = a / b;
            swap(a -= t * b, b);
            swap(u -= t * v, v);
        }
        return ModInt(u);
    }

    ModInt pow(int64_t n) const {
        ModInt ret(1), mul(x);
        while(n > 0) {
            if(n & 1) ret *= mul;
            mul *= mul;
            n >>= 1;
        }
        return ret;
    }

    friend ostream &operator<<(ostream &os, const ModInt &p) {
        return os << p.x;
    }

    friend istream &operator>>(istream &is, ModInt &a) {
        int64_t t;
        is >> t;
        a = ModInt< mod >(t);
        return (is);
    }

    static int get_mod() { return mod; }
};
using modint=ModInt<1000000007>;
template< typename T >
struct Combination {
    vector< T > _fact, _rfact, _inv;

    Combination(int sz) : _fact(sz + 1), _rfact(sz + 1), _inv(sz + 1) {
        _fact[0] = _rfact[sz] = _inv[0] = 1;
        for(int i = 1; i <= sz; i++) _fact[i] = _fact[i - 1] * i;
        _rfact[sz] /= _fact[sz];
        for(int i = sz - 1; i >= 0; i--) _rfact[i] = _rfact[i + 1] * (i + 1);
        for(int i = 1; i <= sz; i++) _inv[i] = _rfact[i] * _fact[i - 1];
    }

    inline T fact(int k) const { return _fact[k]; }

    inline T rfact(int k) const { return _rfact[k]; }

    inline T inv(int k) const { return _inv[k]; }

    T P(int n, int r) const {
        if(r < 0 || n < r) return 0;
        return fact(n) * rfact(n - r);
    }

    T C(int p, int q) const {
        if(q < 0 || p < q) return 0;
        return fact(p) * rfact(q) * rfact(p - q);
    }

    T H(int n, int r) const {
        if(n < 0 || r < 0) return (0);
        return r == 0 ? 1 : C(n + r - 1, r);
    }
};
namespace FastFourierTransform {
    using real = double;

    struct C {
        real x, y;

        C() : x(0), y(0) {}

        C(real x, real y) : x(x), y(y) {}

        inline C operator+(const C &c) const { return C(x + c.x, y + c.y); }

        inline C operator-(const C &c) const { return C(x - c.x, y - c.y); }

        inline C operator*(const C &c) const { return C(x * c.x - y * c.y, x * c.y + y * c.x); }

        inline C conj() const { return C(x, -y); }
    };

    const real PI = acosl(-1);
    int base = 1;
    vector< C > rts = { {0, 0},
                        {1, 0} };
    vector< int > rev = {0, 1};


    void ensure_base(int nbase) {
        if(nbase <= base) return;
        rev.resize(1 << nbase);
        rts.resize(1 << nbase);
        for(int i = 0; i < (1 << nbase); i++) {
            rev[i] = (rev[i >> 1] >> 1) + ((i & 1) << (nbase - 1));
        }
        while(base < nbase) {
            real angle = PI * 2.0 / (1 << (base + 1));
            for(int i = 1 << (base - 1); i < (1 << base); i++) {
                rts[i << 1] = rts[i];
                real angle_i = angle * (2 * i + 1 - (1 << base));
                rts[(i << 1) + 1] = C(cos(angle_i), sin(angle_i));
            }
            ++base;
        }
    }

    void fft(vector< C > &a, int n) {
        assert((n & (n - 1)) == 0);
        int zeros = __builtin_ctz(n);
        ensure_base(zeros);
        int shift = base - zeros;
        for(int i = 0; i < n; i++) {
            if(i < (rev[i] >> shift)) {
                swap(a[i], a[rev[i] >> shift]);
            }
        }
        for(int k = 1; k < n; k <<= 1) {
            for(int i = 0; i < n; i += 2 * k) {
                for(int j = 0; j < k; j++) {
                    C z = a[i + j + k] * rts[j + k];
                    a[i + j + k] = a[i + j] - z;
                    a[i + j] = a[i + j] + z;
                }
            }
        }
    }

    vector< int64_t > multiply(const vector< int > &a, const vector< int > &b) {
        int need = (int) a.size() + (int) b.size() - 1;
        int nbase = 1;
        while((1 << nbase) < need) nbase++;
        ensure_base(nbase);
        int sz = 1 << nbase;
        vector< C > fa(sz);
        for(int i = 0; i < sz; i++) {
            int x = (i < (int) a.size() ? a[i] : 0);
            int y = (i < (int) b.size() ? b[i] : 0);
            fa[i] = C(x, y);
        }
        fft(fa, sz);
        C r(0, -0.25 / (sz >> 1)), s(0, 1), t(0.5, 0);
        for(int i = 0; i <= (sz >> 1); i++) {
            int j = (sz - i) & (sz - 1);
            C z = (fa[j] * fa[j] - (fa[i] * fa[i]).conj()) * r;
            fa[j] = (fa[i] * fa[i] - (fa[j] * fa[j]).conj()) * r;
            fa[i] = z;
        }
        for(int i = 0; i < (sz >> 1); i++) {
            C A0 = (fa[i] + fa[i + (sz >> 1)]) * t;
            C A1 = (fa[i] - fa[i + (sz >> 1)]) * t * rts[(sz >> 1) + i];
            fa[i] = A0 + A1 * s;
        }
        fft(fa, sz >> 1);
        vector< int64_t > ret(need);
        for(int i = 0; i < need; i++) {
            ret[i] = llround(i & 1 ? fa[i >> 1].y : fa[i >> 1].x);
        }
        return ret;
    }
};template< typename T >
struct ArbitraryModConvolution {
    using real = FastFourierTransform::real;
    using C = FastFourierTransform::C;

    ArbitraryModConvolution() = default;

    vector< T > multiply(const vector< T > &a, const vector< T > &b, int need = -1) {
        if(need == -1) need = a.size() + b.size() - 1;
        int nbase = 0;
        while((1 << nbase) < need) nbase++;
        FastFourierTransform::ensure_base(nbase);
        int sz = 1 << nbase;
        vector< C > fa(sz);
        for(int i = 0; i < a.size(); i++) {
            fa[i] = C(a[i].x & ((1 << 15) - 1), a[i].x >> 15);
        }
        fft(fa, sz);
        vector< C > fb(sz);
        if(a == b) {
            fb = fa;
        } else {
            for(int i = 0; i < b.size(); i++) {
                fb[i] = C(b[i].x & ((1 << 15) - 1), b[i].x >> 15);
            }
            fft(fb, sz);
        }
        real ratio = 0.25 / sz;
        C r2(0, -1), r3(ratio, 0), r4(0, -ratio), r5(0, 1);
        for(int i = 0; i <= (sz >> 1); i++) {
            int j = (sz - i) & (sz - 1);
            C a1 = (fa[i] + fa[j].conj());
            C a2 = (fa[i] - fa[j].conj()) * r2;
            C b1 = (fb[i] + fb[j].conj()) * r3;
            C b2 = (fb[i] - fb[j].conj()) * r4;
            if(i != j) {
                C c1 = (fa[j] + fa[i].conj());
                C c2 = (fa[j] - fa[i].conj()) * r2;
                C d1 = (fb[j] + fb[i].conj()) * r3;
                C d2 = (fb[j] - fb[i].conj()) * r4;
                fa[i] = c1 * d1 + c2 * d2 * r5;
                fb[i] = c1 * d2 + c2 * d1;
            }
            fa[j] = a1 * b1 + a2 * b2 * r5;
            fb[j] = a1 * b2 + a2 * b1;
        }
        fft(fa, sz);
        fft(fb, sz);
        vector< T > ret(need);
        for(int i = 0; i < need; i++) {
            int64_t aa = llround(fa[i].x);
            int64_t bb = llround(fb[i].x);
            int64_t cc = llround(fa[i].y);
            aa = T(aa).x, bb = T(bb).x, cc = T(cc).x;
            ret[i] = aa + (bb << 15) + (cc << 30);
        }
        return ret;
    }
};
template< typename T >
struct FormalPowerSeries : vector< T > {
    using vector< T >::vector;
    using P = FormalPowerSeries;

    using MULT = function< P(P, P) >;

    static MULT &get_mult() {
        static MULT mult = nullptr;
        return mult;
    }

    static void set_fft(MULT f) {
        get_mult() = f;
    }

    void shrink() {
        while(this->size() && this->back() == T(0)) this->pop_back();
    }

    P operator+(const P &r) const { return P(*this) += r; }

    P operator+(const T &v) const { return P(*this) += v; }

    P operator-(const P &r) const { return P(*this) -= r; }

    P operator-(const T &v) const { return P(*this) -= v; }

    P operator*(const P &r) const { return P(*this) *= r; }

    P operator*(const T &v) const { return P(*this) *= v; }

    P operator/(const P &r) const { return P(*this) /= r; }

    P operator%(const P &r) const { return P(*this) %= r; }

    P &operator+=(const P &r) {
        if(r.size() > this->size()) this->resize(r.size());
        for(int i = 0; i < r.size(); i++) (*this)[i] += r[i];
        return *this;
    }

    P &operator+=(const T &r) {
        if(this->empty()) this->resize(1);
        (*this)[0] += r;
        return *this;
    }

    P &operator-=(const P &r) {
        if(r.size() > this->size()) this->resize(r.size());
        for(int i = 0; i < r.size(); i++) (*this)[i] -= r[i];
        shrink();
        return *this;
    }

    P &operator-=(const T &r) {
        if(this->empty()) this->resize(1);
        (*this)[0] -= r;
        shrink();
        return *this;
    }

    P &operator*=(const T &v) {
        const int n = (int) this->size();
        for(int k = 0; k < n; k++) (*this)[k] *= v;
        return *this;
    }

    P &operator*=(const P &r) {
        if(this->empty() || r.empty()) {
            this->clear();
            return *this;
        }
        assert(get_mult() != nullptr);
        return *this = get_mult()(*this, r);
    }

    P &operator%=(const P &r) {
        return *this -= *this / r * r;
    }

    P operator-() const {
        P ret(this->size());
        for(int i = 0; i < this->size(); i++) ret[i] = -(*this)[i];
        return ret;
    }

    P &operator/=(const P &r) {
        if(this->size() < r.size()) {
            this->clear();
            return *this;
        }
        int n = this->size() - r.size() + 1;
        return *this = (rev().pre(n) * r.rev().inv(n)).pre(n).rev(n);
    }

    P pre(int sz) const {
        return P(begin(*this), begin(*this) + min((int) this->size(), sz));
    }

    P operator>>(int sz) const {
        if(this->size() <= sz) return {};
        P ret(*this);
        ret.erase(ret.begin(), ret.begin() + sz);
        return ret;
    }

    P operator<<(int sz) const {
        P ret(*this);
        ret.insert(ret.begin(), sz, T(0));
        return ret;
    }

    P rev(int deg = -1) const {
        P ret(*this);
        if(deg != -1) ret.resize(deg, T(0));
        reverse(begin(ret), end(ret));
        return ret;
    }

    P diff() const {
        const int n = (int) this->size();
        P ret(max(0, n - 1));
        for(int i = 1; i < n; i++) ret[i - 1] = (*this)[i] * T(i);
        return ret;
    }

    P integral() const {
        const int n = (int) this->size();
        P ret(n + 1);
        ret[0] = T(0);
        for(int i = 0; i < n; i++) ret[i + 1] = (*this)[i] / T(i + 1);
        return ret;
    }

    // F(0) must not be 0
    P inv(int deg = -1) const {
        assert(((*this)[0]) != T(0));
        const int n = (int) this->size();
        if(deg == -1) deg = n;
        P ret({T(1) / (*this)[0]});
        for(int i = 1; i < deg; i <<= 1) {
            ret = (ret + ret - ret * ret * pre(i << 1)).pre(i << 1);
        }
        return ret.pre(deg);
    }

    // F(0) must be 1
    P log(int deg = -1) const {
        assert((*this)[0] == 1);
        const int n = (int) this->size();
        if(deg == -1) deg = n;
        return (this->diff() * this->inv(deg)).pre(deg - 1).integral();
    }

    P sqrt(int deg = -1) const {
        const int n = (int) this->size();
        if(deg == -1) deg = n;

        if((*this)[0] == T(0)) {
            for(int i = 1; i < n; i++) {
                if((*this)[i] != T(0)) {
                    if(i & 1) return {};
                    if(deg - i / 2 <= 0) break;
                    auto ret = (*this >> i).sqrt(deg - i / 2) << (i / 2);
                    if(ret.size() < deg) ret.resize(deg, T(0));
                    return ret;
                }
            }
            return P(deg, 0);
        }

        P ret({T(1)});
        T inv2 = T(1) / T(2);
        for(int i = 1; i < deg; i <<= 1) {
            ret = (ret + pre(i << 1) * ret.inv(i << 1)) * inv2;
        }
        return ret.pre(deg);
    }

    // F(0) must be 0
    P exp(int deg = -1) const {
        assert((*this)[0] == T(0));
        const int n = (int) this->size();
        if(deg == -1) deg = n;
        P ret({T(1)});
        for(int i = 1; i < deg; i <<= 1) {
            ret = (ret * (pre(i << 1) + T(1) - ret.log(i << 1))).pre(i << 1);
        }
        return ret.pre(deg);
    }

    P pow(int64_t k, int deg = -1) const {
        const int n = (int) this->size();
        if(deg == -1) deg = n;
        for(int i = 0; i < n; i++) {
            if((*this)[i] != T(0)) {
                T rev = T(1) / (*this)[i];
                P C(*this * rev);
                P D(n - i);
                for(int j = i; j < n; j++) D[j - i] = C[j];
                D = (D.log() * k).exp() * (*this)[i].pow(k);
                P E(deg);
                if(i * k > deg) return E;
                auto S = i * k;
                for(int j = 0; j + S < deg && j < D.size(); j++) E[j + S] = D[j];
                return E;
            }
        }
        return *this;
    }


    T eval(T x) const {
        T r = 0, w = 1;
        for(auto &v : *this) {
            r += w * v;
            w *= x;
        }
        return r;
    }
};
template< typename T >
T factorial(int64_t n) {
    if(n >= T::get_mod()) return 0;
    if(n == 0) return 1;

    const int64_t sn = sqrt(n);
    const T sn_inv = T(1) / sn;

    Combination< modint > comb(sn);
    using P = vector< T >;

    ArbitraryModConvolution< T > fft;
    using FPS = FormalPowerSeries< T >;
    auto mult = [&](const typename FPS::P &a, const typename FPS::P &b) {
      auto ret = fft.multiply(a, b);
      return typename FPS::P(ret.begin(), ret.end());
    };
    FPS::set_fft(mult);


    auto shift = [&](const P &f, T dx) {
      int n = (int) f.size();
      T a = dx * sn_inv;
      auto p1 = P(f);
      for(int i = 0; i < n; i++) {
          T d = comb.rfact(i) * comb.rfact((n - 1) - i);
          if(((n - 1 - i) & 1)) d = -d;
          p1[i] *= d;
      }
      auto p2 = P(2 * n);
      for(int i = 0; i < p2.size(); i++) {
          p2[i] = (a.x + i - n) <= 0 ? 1 : a + i - n;
      }
      for(int i = 1; i < p2.size(); i++) {
          p2[i] *= p2[i - 1];
      }
      T prod = p2[2 * n - 1];
      T prod_inv = T(1) / prod;
      for(int i = 2 * n - 1; i > 0; --i) {
          p2[i] = prod_inv * p2[i - 1];
          prod_inv *= a + i - n;
      }
      p2[0] = prod_inv;
      auto p3 = fft.multiply(p1, p2, (int) p2.size());
      p1 = P(p3.begin() + p1.size(), p3.begin() + p2.size());
      prod = 1;
      for(int i = 0; i < n; i++) {
          prod *= a + n - 1 - i;
      }
      for(int i = n - 1; i >= 0; --i) {
          p1[i] *= prod;
          prod *= p2[n + i] * (a + i - n);
      }
      return p1;
    };
    function< P(int) > rec = [&](int64_t n) {
      if(n == 1) return P({1, 1 + sn});
      int64_t nh = n >> 1;
      auto a1 = rec(nh);
      auto a2 = shift(a1, nh);
      auto b1 = shift(a1, sn * nh);
      auto b2 = shift(a1, sn * nh + nh);
      for(int i = 0; i <= nh; i++) a1[i] *= a2[i];
      for(int i = 1; i <= nh; i++) a1.emplace_back(b1[i] * b2[i]);
      if(n & 1) {
          for(int64_t i = 0; i < n; i++) {
              a1[i] *= n + 1LL * sn * i;
          }
          T prod = 1;
          for(int64_t i = 1LL * n * sn; i < 1LL * n * sn + n; i++) {
              prod *= (i + 1);
          }
          a1.push_back(prod);
      }
      return a1;
    };
    auto vs = rec(sn);
    T ret = 1;
    for(int64_t i = 0; i < sn; i++) ret *= vs[i];
    for(int64_t i = 1LL * sn * sn + 1; i <= n; i++) ret *= i;
    return ret;
}
signed main(signed argc, char* argv[]) {
    cin.tie(0);
    ios::sync_with_stdio(false);
    const int MOD = 1000000007;
    int n,a,b;
    scanf("%d %d %d",&n,&a,&b);
    ModInt<MOD> ans=ModInt<MOD>(2).pow(n);
    ans-=factorial<modint>(n)/(factorial<modint>(a)*factorial<modint>(n-a));
    ans-=factorial<modint>(n)/(factorial<modint>(b)*factorial<modint>(n-b));
    printf("%d",(ans-1).x);
}


Measured memory_bytes: 2900