#include <stdio.h>

const int Mod = 1000000007;
long long fact[200001], fact_inv[200001];

long long div_mod(long long x, long long y, long long z)
{
	if (x % y == 0) return x / y;
	else return (div_mod((1 + x / y) * y - x, (z % y), y) * z + x) / y;
}

long long combination(int n, int k)
{
	if (k < 0 || n < k) return 0;
	return fact[n] * fact_inv[k] % Mod * fact_inv[n-k] % Mod;
}

int main()
{
	int i, N, K;
	scanf("%d %d", &N, &K);
	for (i = 1, fact[0] = 1; i <= N; i++) fact[i] = fact[i-1] * i % Mod;
	for (i = N - 1, fact_inv[N] = div_mod(1, fact[N], Mod); i >= 0; i--) fact_inv[i] = fact_inv[i+1] * (i + 1) % Mod;
	
	long long ans = 0, tmp;
	for (i = 0, tmp = 500000004; i < N && i < K; i++) {
		tmp = tmp * 2 * fact[i] % Mod * fact_inv[i+1] % Mod * (K - i) % Mod;
		ans += combination(N - 1, i) * tmp % Mod;
	}
	printf("%lld\n", ans % Mod);
	fflush(stdout);
	return 0;
}