#include <stdio.h>

#define MOD 1000000007
typedef long long int LL;

LL inv(LL n) {
	LL ans = 1;
	int b = MOD - 2;
	
	while(b) {
		if(b % 2) { ans *= n; ans %= MOD; }
		n *= n; n %= MOD;
		b /= 2;
	}
	
	return ans;
}

LL pow_mod(LL a, LL b) {
	LL ans = 1;
	while(b) {
		if(b % 2) { ans *= a; ans %= MOD; }
		a *= a; a %= MOD;
		b /= 2;
	}
	
	return ans;
}

LL comb = 1;
LL comb_mod(LL a, LL b) {
	LL ans = comb;
	
	comb *= a - (b); comb %= MOD;
	comb *= inv(b + 1); comb %= MOD;
	
	return ans;
}

int main() {
	LL n, m;
	scanf("%lld%lld", &n, &m);
	
	LL ans = 0;
	if(n >= m) {
		for(LL i = 0; i < m; i++) {
			LL s = (i % 2 == 0 ? 1 : -1);
			ans += ( pow_mod(m - i, n) * comb_mod(m, i) % MOD * s + MOD ) % MOD;
			ans %= MOD;
		}
	}
	
	printf("%lld\n", ans);
	
	return 0;
}