#include "bits/stdc++.h"
using namespace std;
#define int long long
const int MAXN = 2e5 + 10;
const int MOD = 1e9 + 7;
mt19937_64 rng((int)std::chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x, int y) {
int u = uniform_int_distribution<int>(x, y)(rng); return u;
}
int bm(int b, int p) {
if(p==0) return 1 % MOD;
int r = bm(b, p >> 1);
if(p&1) return (((r*r) % MOD) * b) % MOD;
return (r*r) % MOD;
}
int inv(int b) {
return bm(b, MOD-2);
}
int fastlog(int x) {
return (x == 0 ? -1 : 64 - __builtin_clzll(x) - 1);
}
void printcase(int i) { cout << "Case #" << i << ": "; }
int fac[MAXN];
int ncr(int n, int r) {
int b = fac[n] * inv(fac[r]);
b %= MOD;
b *= inv(fac[n-r]);
b %= MOD;
return b;
}
void solve(int tc) {
// Wtf eulerian numbers
// In arvindf232's language - "uninteresting" and "standard"
// Copy wiki and dump into oeis
int n;
cin >> n;
int k;
cin >> k;
fac[0] = 1;
for(int i=1; i<=n+1; i++) {
fac[i] = (fac[i-1] * i) % MOD;
}
int ans = 0;
for(int i=0; i<=k; i++) {
int u = 1;
if(i&1) u = MOD-1;
u *= ncr(n+1, i);
u %= MOD;
u *= bm(k-i, n);
u %= MOD;
ans += u;
ans %= MOD;
}
cout << ans << "\n";
}
int32_t main() {
ios::sync_with_stdio(0); cin.tie(0);
int t = 1; //cin >> t;
for(int i=1; i<=t; i++) solve(i);
}
