#include <stdio.h>

const int Mod = 1000000007;
int comb[8001][8001], comb_sum[8001][8001];

long long solve_even(int N, int M)
{
	int i, j;
	long long ans = 0;
	for (i = 0; i <= N / 2; i++) {
		for (j = 0; j < N / 2 && i + j <= M; j++) {
			if (i + j == 0) continue;
			ans += (long long)comb_sum[M-1][i+j-1] * comb[N][i] % Mod * comb[N-i][j] % Mod;
		}
	}
	if (M % 2 == 0) ans++;
	return ans % Mod;
}

long long solve_odd(int N, int M)
{
	int i, j;
	long long ans = 0;
	for (i = 0; i <= N / 2; i++) {
		for (j = 0; j <= N / 2 && i + j <= M; j++) {
			if (i + j == 0) continue;
			ans += (long long)comb_sum[M-1][i+j-1] * comb[N][i] % Mod * comb[N-i][j] % Mod;
		}
	}
	if (M > N) {
		for (i = 0; i <= N / 2; i++) {
			for (j = 0; j <= N / 2 && i + j <= M - N; j++) {
				if (i + j == 0) continue;
				ans += (long long)comb_sum[M-N-1][i+j-1] * comb[N][i] % Mod * comb[N-i][j] % Mod;
			}
		}
	}
	if (M % 2 == 0 || M >= N) ans++;
	return ans % Mod;
}

int main()
{
	int i, j, N, M;
	scanf("%d %d", &N, &M);
	for (i = 1, comb[0][0] = 1, comb_sum[0][0] = 1; i <= N + M; i++) {
		for (j = 1, comb[i][0] = 1, comb[i][i] = 1; j < i; j++) {
			comb[i][j] = comb[i-1][j-1] + comb[i-1][j];
			if (comb[i][j] >= Mod) comb[i][j] -= Mod;
		}
		for (j = 0; j <= i; j++) {
			comb_sum[i][j] = ((i - 2 >= j)? comb_sum[i-2][j]: 0) + comb[i][j];
			if (comb_sum[i][j] >= Mod) comb_sum[i][j] -= Mod;
		}
	}
	if (N % 2 == 0) printf("%lld\n", solve_even(N, M));
	else printf("%lld\n", solve_odd(N, M));
	fflush(stdout);
	return 0;
}