#include <bits/stdc++.h>
#define int long long
#define ii pair <int, int>
#define F first
#define S second
using namespace std;
const int mod = 1e9 + 7;
const int N = 4e3 + 5;
void add(int &a, int b){
a += b;
if (a >= mod) a -= mod;
if (a < 0) a += mod;
}
int mu(int a, int b){
if (b == 0) return 1;
if (b % 2 == 1) return 1ll * mu(a, b - 1) * a % mod;
int c = mu(a, b / 2);
return 1ll * c * c % mod;
}
int dp[N][N], C[N][N];
int n, m;
int gt[N], re_2[N];
int c(int b, int a){
return 1ll * (1ll * gt[a] * mu(gt[b], mod - 2) % mod) * mu(gt[a - b], mod - 2) % mod;
}
void solve(){
cin >> n >> m;
gt[0] = 1;
for (int i = 1; i <= 2 * n; ++ i) gt[i] = 1ll * gt[i - 1] * i % mod;
int kk = mu(2, mod - 2);
re_2[0] = 1;
for (int i = 1; i <= n; ++ i) re_2[i] = 1ll * re_2[i - 1] * kk % mod;
for (int i = 0; i <= 2 * n; ++ i) for (int j = 0; j <= i; ++ j) C[j][i] = c(j, i);
dp[0][0] = 1;
for (int i = 1; i <= m; ++ i){
int val = (2 * n - i) / m + 1;
for (int j = 0; j <= n; ++ j){
//dp[i][j] = dp[i - 1][j];
for (int k = 0; k <= min(j, val / 2); ++ k){
int zk = 1ll * dp[i - 1][j - k] * C[2 * k][val] % mod;
//zk = 1ll * zk * re_2[k] % mod;
zk = 1ll * zk * gt[2 * k] % mod;
zk = 1ll * zk * C[k][n - j + k] % mod;
add(dp[i][j], zk);
}
//cout << dp[i][j] << ' ';
}
//cout << endl;
}
int ans = 0;
for (int i = 0; i <= n; ++ i){
int val = 1ll * dp[m][i] * gt[(n - i) * 2] % mod;
//val = 1ll * val * re_2[n - i] % mod;
if (i % 2 == 0) add(ans, val);
else add(ans, -val);
}
cout << ans;
}
signed main(){
//freopen("code.inp", "r", stdin);
//freopen("code.out", "w", stdout);
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t = 1;
while (t --) solve();
return 0;
}
