#include <stdio.h>
#include <stdint.h>
#include <string.h>

int ri() {
	int n;
	scanf("%d", &n);
	return n;
}

#define MOD 1000000007

int main() {
	int p = ri();
	int k = ri();
	int dp[2] = {1, 0};
	for (int i = 0; i < k; i++) {
		int next[2] = {
			(int) ((dp[0] + dp[1] + (int64_t) dp[0] * p + dp[1]) % MOD),
			(int) (((int64_t) (dp[0] + dp[1]) * (p - 1) + (int64_t) dp[1] * (p - 1)) % MOD)
		};
		memcpy(dp, next, sizeof(next));
	}
	printf("%d\n", dp[0]);
	return 0;
}