#include <algorithm>
#include <iostream>
#include <numeric>
#include <string>
#include <tuple>
#include <utility>
#include <vector>
#include <limits>

#define rep(i, a, b) for (int i = int(a); i < int(b); i++)
using namespace std;
using ll = long long int;  // NOLINT
using P = pair<ll, ll>;

// clang-format off
#ifdef _DEBUG_
#define dump(...) do{ cerr << __LINE__ << ":\t" << #__VA_ARGS__ << " = "; debug_print(__VA_ARGS__); } while(false)
template<typename T, typename... Ts> void debug_print(const T &t, const Ts &...ts) { cerr << t; ((cerr << ", " << ts), ...); cerr << endl; }
#else
#define dump(...) do{ } while(false)
#endif
template<typename T> vector<T> make_v(size_t a, T b) { return vector<T>(a, b); }
template<typename... Ts> auto make_v(size_t a, Ts... ts) { return vector<decltype(make_v(ts...))>(a, make_v(ts...)); }
template<typename T> bool chmin(T &a, const T& b) { if (a > b) {a = b; return true; } return false; }
template<typename T> bool chmax(T &a, const T& b) { if (a < b) {a = b; return true; } return false; }
template<typename T, typename... Ts> void print(const T& t, const Ts&... ts) { cout << t; ((cout << ' ' << ts), ...); cout << '\n'; }
template<typename... Ts> void input(Ts&... ts) { (cin >> ... >> ts); }
template<typename T> istream &operator,(istream &in, T &t) { return in >> t; }
struct Inf { template<typename T> constexpr operator T() { return numeric_limits<T>::max() / 2; } };
// clang-format on

template<ll MOD>
class ModInt {
    ll n;
    auto constexpr inverse() const {
        return this->pow(*this, this->mod - 2);
    }

public:
    constexpr static ll mod = MOD;
    using mint = ModInt<MOD>;

    constexpr ModInt() : n(0) {}
    constexpr ModInt(const ll &nn) : n(((nn % MOD) + MOD) % MOD) {}
    constexpr mint operator+=(const mint &m) {
        n += m.n;
        if (n >= mint::mod) n -= mint::mod;
        return *this;
    }
    constexpr mint operator-=(const mint &m) {
        n -= m.n;
        if (n < 0) n += mint::mod;
        return *this;
    }
    constexpr mint operator*=(const mint &m) {
        n *= m.n;
        if (n >= mint::mod) n %= mint::mod;
        return *this;
    }
    constexpr mint operator/=(const mint &m) {
        return (*this) *= m.inverse();
    }
    friend constexpr mint operator+(mint t, const mint &m) {
        return t += m;
    }
    friend constexpr mint operator-(mint t, const mint &m) {
        return t -= m;
    }
    friend constexpr mint operator*(mint t, const mint &m) {
        return t *= m;
    }
    friend constexpr mint operator/(mint t, const mint &m) {
        return t /= m;
    }
    constexpr mint operator=(const ll &l) {
        n = l % mint::mod;
        if (n < 0) n += mint::mod;
        return *this;
    }
    friend ostream &operator<<(ostream &out, const mint &m) {
        out << m.n;
        return out;
    }
    friend istream &operator>>(istream &in, mint &m) {
        ll l;
        in >> l;
        m = l;
        return in;
    }
    static constexpr auto pow(const mint &x, ll p) {
        mint ans = 1;
        for (auto m = x; p > 0; p /= 2, m *= m) {
            if (p % 2) ans *= m;
        }
        return ans;
    }
    constexpr ll get_raw() const {
        return n;
    }
};
using mint = ModInt<1000000007>::mint;
constexpr mint operator"" _m(unsigned long long m) {
    return mint(m);
}

class Combination {
    vector<mint> factor, rfactor;

public:
    Combination(int n) {
        factor.resize(n, 1);
        rfactor.resize(n, 1);
        for (int i = 1; i < n; i++) {
            factor[i] = i * factor[i - 1];
        }
        rfactor[n - 1] = 1 / factor[n - 1];
        for (int i = n - 1; i > 0; i--) {
            rfactor[i - 1] = rfactor[i] * i;
        }
    }
    mint nCr(int n, int r) {
        if (n < r) return 0;
        if (n < mint::mod) return factor[n] * rfactor[r] * rfactor[n - r];
        // Lucasの定理
        mint res = 1;
        while (n || r) {
            int nn = n % mint::mod, rr = r % mint::mod;
            n /= mint::mod;
            r /= mint::mod;
            res *= nCr(nn, rr);
        }
        return res;
    }
    mint nPr(int n, int r) {
        return factor[n] * rfactor[n - r];
    }
    mint nSr(ll n, int r) {
        mint ans = 0;
        for (int i = r, s = 1; i >= 0; i--, s *= -1) {
            ans += s * nCr(r, i) * mint::pow(i, n);
        }
        return ans * rfactor[r];
    }
    mint factorial(int n) {
        return factor[n];
    }
};

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int n, m;
    cin >> n >> m;
    Combination comb(n + m + 10);
    mint ans = 0;
    rep(i, n, m + 1) {
        ans += comb.nCr(i, n);
    }
    print(ans);
    return 0;
}