// // Created by liasa on 07/02/2026. // #include <bits/stdc++.h> using namespace std; #define ll long long #define v vector #define lp(i, s, e) for (ll i = s; i < e; ++i) const ll mod = 1e9 + 7; int main() { ios_base::sync_with_stdio(0); cin.tie(0); ll n, k; cin >> n >> k; v<v<ll>> dp(n + 1, v<ll>(k + 1)); dp[1][1] = 1; lp(i, 2, n + 1) { lp(j, 1, k + 1) { dp[i][j] = ((j * dp[i - 1][j]) % mod + (i - j + 1) * dp[i - 1][j - 1]) % mod; } } ll ans = dp[n][k]; cout << ans << '\n'; }