#include <stdio.h>
#include <stdlib.h>

const int Mod = 1000000007;

long long fact[1000001], fact_inv[1000001];

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) return 0;
	return fact[n] * fact_inv[k] % Mod * fact_inv[n-k] % Mod;
}

long long naive(int N, int M)
{
	int i, j, k;
	long long ans = 0;
	for (i = M; i <= N; i++) {
		k = N;
		ans += k + N;
		for (j = 1, k -= 2; j <= i && j <= N - i && k >= 0; j++, k -= 2) ans += (k + N) * (combination(N, j) - combination(N, j - 1) + Mod) % Mod;
	}
	return ans % Mod;
}

long long solve(int N, int M)
{
	int i, j, k;
	long long ans = 0;
	if (M * 2 >= N) {
		for (i = 0, j = N - M + 1, k = N * 2; j > 0; i++, j--, k -= 2) ans += k * (combination(N, i) - combination(N, i - 1) + Mod) % Mod * j % Mod;
	} else {
		for (i = 0, j = N + 1, k = N * 2; j > 0; i++, j -= 2, k -= 2) ans += k * (combination(N, i) - combination(N, i - 1) + Mod) % Mod * j % Mod;
		for (i = 0, j = M, k = N * 2; j > 0; i++, j--, k -= 2) ans += Mod - k * (combination(N, i) - combination(N, i - 1) + Mod) % Mod * j % Mod;
	}
	return ans % Mod;
}

int main()
{
	int i, N, M;
	scanf("%d %d", &N, &M);
	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;
	printf("%lld\n", solve(N, M));
	fflush(stdout);
	return 0;
}