#include using namespace std; using lint = long long; template using V = vector; template using VV = V< V >; template struct ModInt { using M = ModInt; unsigned v; ModInt() : v(0) {} ModInt(auto x) : v(x >= 0 ? x % P : (P - -x % P) % P) {} constexpr ModInt(unsigned v, int) : v(v) {} static constexpr unsigned p() { return P; } M operator+() const { return *this; } M operator-() const { return {v ? P - v : 0, 0}; } explicit operator bool() const noexcept { return v; } bool operator!() const noexcept { return !(bool) *this; } M operator*(M r) const { return M(*this) *= r; } M operator/(M r) const { return M(*this) /= r; } M operator+(M r) const { return M(*this) += r; } M operator-(M r) const { return M(*this) -= r; } bool operator==(M r) const { return v == r.v; } bool operator!=(M r) const { return !(*this == r); } M& operator*=(M r) { v = (uint64_t) v * r.v % P; return *this; } M& operator/=(M r) { return *this *= r.inv(); } M& operator+=(M r) { if ((v += r.v) >= P) v -= P; return *this; } M& operator-=(M r) { if ((v += P - r.v) >= P) v -= P; return *this; } M inv() const { int a = v, b = P, x = 1, u = 0; while (b) { int q = a / b; swap(a -= q * b, b); swap(x -= q * u, u); } assert(a == 1); return x; } M pow(auto n) const { if (n < 0) return pow(-n).inv(); M res = 1; for (M a = *this; n; a *= a, n >>= 1) if (n & 1) res *= a; return res; } friend M operator*(auto l, M r) { return M(l) *= r; } friend M operator/(auto l, M r) { return M(l) /= r; } friend M operator+(auto l, M r) { return M(l) += r; } friend M operator-(auto l, M r) { return M(l) -= r; } friend ostream& operator<<(ostream& os, M r) { return os << r.v; } friend istream& operator>>(istream& is, M& r) { lint x; is >> x; r = x; return is; } friend bool operator==(auto l, M r) { return M(l) == r; } friend bool operator!=(auto l, M r) { return !(l == r); } }; using Mint = ModInt<(unsigned) 1e9 + 7>; V fact, ifact, inv, powB; void init(int n, int B = 2) { fact.resize(n + 1); fact[0] = 1; for (int i = 1; i <= n; ++i) { fact[i] = i * fact[i - 1]; } ifact.resize(n + 1); ifact[n] = fact[n].inv(); for (int i = n; i > 0; --i) { ifact[i - 1] = i * ifact[i]; } inv.resize(n + 1); inv[1] = 1; for (int i = 2; i <= n; ++i) { int q = Mint::p() / i; inv[i] = -q * inv[Mint::p() - i * q]; } powB.resize(n + 1); powB[0] = 1; for (int i = 0; i < n; ++i) { powB[i + 1] = powB[i] * B; } } Mint comb(int n, int r) { if (r < 0 or r > n) return 0; return fact[n] * ifact[r] * ifact[n - r]; } int main() { cin.tie(nullptr); ios::sync_with_stdio(false); int n, m; cin >> n >> m; init(m); Mint res; for (int k = m / 2 % n; k <= m; k += n) { res += comb(m, k); } cout << res << '\n'; }