//#include #include #include #include #include #include #include #include // string, to_string, stoi #include // vector #include // min, max, swap, sort, reverse, lower_bound, upper_bound #include // pair, make_pair #include // tuple, make_tuple #include // int64_t, int*_t #include // printf #include // map #include // queue, priority_queue #include // set #include // stack #include // deque #include // unordered_map #include // unordered_set #include // bitset #include // isupper, islower, isdigit, toupper, tolower using namespace std; //using namespace atcoder; using ll = long long; #define all(A) A.begin(),A.end() using vll = vector; #define rep(i, n) for (long long i = 0; i < (long long)(n); i++) using Graph = vector>; vector fact, factinv, inv; ll mod = 1e9 + 7; void prenCkModp(ll n) { fact.resize(n + 5); factinv.resize(n + 5); inv.resize(n + 5); fact.at(0) = fact.at(1) = 1; factinv.at(0) = factinv.at(1) = 1; inv.at(1) = 1; for (ll i = 2; i < n + 5; i++) { fact.at(i) = (fact.at(i - 1) * i) % mod; inv.at(i) = mod - (inv.at(mod % i) * (mod / i)) % mod; factinv.at(i) = (factinv.at(i - 1) * inv.at(i)) % mod; } } ll nCk(ll n, ll k) { if (n < k) return 0; return fact.at(n) * (factinv.at(k) * factinv.at(n - k) % mod) % mod; } int main() { ll N, M; cin >> N >> M; ll an = 0; prenCkModp(M); for (ll k = N; k <= M; k++) { an += nCk(k, N); an %= mod; } cout <