#include <bits/stdc++.h>
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<ll, ll> pll;
typedef pair<ull, ull> pull;
typedef pair<int, int> pii;
typedef pair<ld, ld> pld;
const ll mod = 1e9+7;
ll n, k;
ll dp[3009][3009];
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
//freopen("in.txt", "r", stdin);
//freopen("out.txt", "w", stdout);
cin >> n >> k;
for(ll i = 1; i < n; ++i){
dp[i][1] = 1;
for(ll j = 1; j <= k; ++j){
dp[i+1][j] += dp[i][j]*j%mod;
dp[i+1][j] %= mod;
dp[i+1][j+1] += dp[i][j]*(i-j+1)%mod;
dp[i+1][j+1] %= mod;
}
}
cout << dp[n][k] << '\n';
}
