This documentation is automatically generated by online-judge-tools/verification-helper
#define PROBLEM "https://onlinejudge.u-aizu.ac.jp/courses/library/7/DPL/5/DPL_5_B"
#include <bits/stdc++.h> // clang-format off
using Int = long long;
#define REP_(i, a_, b_, a, b, ...) for (Int i = (a), lim##i = (b); i < lim##i; i++)
#define REP(i, ...) REP_(i, __VA_ARGS__, __VA_ARGS__, 0, __VA_ARGS__)
struct SetupIO { SetupIO() { std::cin.tie(nullptr), std::ios::sync_with_stdio(false), std::cout << std::fixed << std::setprecision(13); } } setup_io;
#ifndef _MY_DEBUG
#define dump(...)
#endif // clang-format on
/**
* author: knshnb
* created: Sun Apr 12 16:50:17 JST 2020
**/
#define CALL_FROM_TEST
#include "../../src/Math/ModInt.hpp"
#include "../../src/Math/Combination.hpp"
#undef CALL_FROM_TEST
using mint = ModInt<1000000007>;
signed main() {
Combination<mint> comb;
Int n, k;
std::cin >> n >> k;
std::cout << (n > k ? 0 : comb.fact[k] / comb.fact[k - n]) << std::endl;
}
#line 1 "test/aoj/DPL_5_B.test.cpp"
#define PROBLEM "https://onlinejudge.u-aizu.ac.jp/courses/library/7/DPL/5/DPL_5_B"
#include <bits/stdc++.h> // clang-format off
using Int = long long;
#define REP_(i, a_, b_, a, b, ...) for (Int i = (a), lim##i = (b); i < lim##i; i++)
#define REP(i, ...) REP_(i, __VA_ARGS__, __VA_ARGS__, 0, __VA_ARGS__)
struct SetupIO { SetupIO() { std::cin.tie(nullptr), std::ios::sync_with_stdio(false), std::cout << std::fixed << std::setprecision(13); } } setup_io;
#ifndef _MY_DEBUG
#define dump(...)
#endif // clang-format on
/**
* author: knshnb
* created: Sun Apr 12 16:50:17 JST 2020
**/
#define CALL_FROM_TEST
#line 1 "src/Math/ModInt.hpp"
template <class T> T pow(T x, long long n, const T UNION = 1) {
T ret = UNION;
while (n) {
if (n & 1) ret *= x;
x *= x;
n >>= 1;
}
return ret;
}
/// @docs src/Math/ModInt.md
template <int Mod> struct ModInt {
int x;
static int& runtime_mod() {
static int runtime_mod_;
return runtime_mod_;
}
// テンプレート引数が負のときは実行時ModInt
static constexpr int mod() { return Mod < 0 ? runtime_mod() : Mod; }
static std::unordered_map<int, int>& to_inv() {
static std::unordered_map<int, int> to_inv_;
return to_inv_;
}
static void set_runtime_mod(int mod) {
static_assert(Mod < 0, "template parameter Mod must be negative for runtime ModInt");
runtime_mod() = mod, to_inv().clear();
}
ModInt() : x(0) {}
ModInt(long long x_) {
if ((x = x_ % mod() + mod()) >= mod()) x -= mod();
}
ModInt& operator+=(ModInt rhs) {
if ((x += rhs.x) >= mod()) x -= mod();
return *this;
}
ModInt& operator*=(ModInt rhs) {
x = (unsigned long long)x * rhs.x % mod();
return *this;
}
ModInt& operator-=(ModInt rhs) {
if ((x -= rhs.x) < 0) x += mod();
return *this;
}
ModInt& operator/=(ModInt rhs) {
ModInt inv = to_inv().count(rhs.x) ? to_inv()[rhs.x] : (to_inv()[rhs.x] = pow(rhs, mod() - 2).x);
return *this *= inv;
}
ModInt operator-() const { return -x < 0 ? mod() - x : -x; }
ModInt operator+(ModInt rhs) const { return ModInt(*this) += rhs; }
ModInt operator*(ModInt rhs) const { return ModInt(*this) *= rhs; }
ModInt operator-(ModInt rhs) const { return ModInt(*this) -= rhs; }
ModInt operator/(ModInt rhs) const { return ModInt(*this) /= rhs; }
bool operator==(ModInt rhs) const { return x == rhs.x; }
bool operator!=(ModInt rhs) const { return x != rhs.x; }
// 計算結果をmapに保存するべき乗
ModInt save_pow(int n) const {
static std::map<std::pair<int, int>, int> tbl_pow;
if (tbl_pow.count({x, n})) return tbl_pow[{x, n}];
if (n == 0) return 1;
if (n % 2) return tbl_pow[{x, n}] = (*this * save_pow(n - 1)).x;
return tbl_pow[{x, n}] = (save_pow(n / 2) * save_pow(n / 2)).x;
}
// 1 + r + r^2 + ... + r^(n-1)を逆元がない(modが素数でない)場合に計算
static ModInt geometric_progression(ModInt r, int n) {
if (n == 0) return 0;
if (n % 2) return geometric_progression(r, n - 1) + r.save_pow(n - 1);
return geometric_progression(r, n / 2) * (r.save_pow(n / 2) + 1);
}
// a + r * (a - d) + r^2 * (a - 2d) + ... + r^(n-1) * (a - (n - 1)d)
static ModInt linear_sum(ModInt r, ModInt a, ModInt d, int n) {
if (n == 0) return 0;
if (n % 2) return linear_sum(r, a, d, n - 1) + r.save_pow(n - 1) * (a - d * (n - 1));
return linear_sum(r, a, d, n / 2) * (r.save_pow(n / 2) + 1) -
d * (n / 2) * r.save_pow(n / 2) * geometric_progression(r, n / 2);
}
friend std::ostream& operator<<(std::ostream& s, ModInt<Mod> a) { return s << a.x; }
friend std::istream& operator>>(std::istream& s, ModInt<Mod>& a) {
long long tmp;
s >> tmp;
a = ModInt<Mod>(tmp);
return s;
}
friend std::string to_string(ModInt<Mod> a) { return std::to_string(a.x); }
};
#ifndef CALL_FROM_TEST
using mint = ModInt<1000000007>;
#endif
#line 1 "src/Math/Combination.hpp"
template <class T> struct Combination {
std::vector<T> fact, fact_inv;
Combination(int n = 1000003) : fact(n + 1, 1), fact_inv(n + 1) {
for (int i = 0; i < n; i++) fact[i + 1] = fact[i] * (i + 1);
fact_inv[n] = (T)1 / fact[n];
for (int i = n - 1; i >= 0; i--) fact_inv[i] = fact_inv[i + 1] * (i + 1);
// for (int i = 0; i < n + 1; i++) assert(fact[i] * fact_inv[i] == 1);
}
T operator()(int n, int r) { return fact[n] * fact_inv[r] * fact_inv[n - r]; }
};
#line 20 "test/aoj/DPL_5_B.test.cpp"
#undef CALL_FROM_TEST
using mint = ModInt<1000000007>;
signed main() {
Combination<mint> comb;
Int n, k;
std::cin >> n >> k;
std::cout << (n > k ? 0 : comb.fact[k] / comb.fact[k - n]) << std::endl;
}