#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1e9 + 7;
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
// idea: spam PIE
// 2^n * # of ways to assign
// n! - n * dp[1] + n*(n - 1)*dp[2] - n*(n - 1)*(n - 2)*dp[3] + ...
// dp[i] = # of ways to assign i pairs s.t. they are all m*k apart
int n, m;
cin >> n >> m;
auto modpow = [&](int a, int b) {
int ans = 1;
while (b) {
if (b & 1) {
ans = 1ll * a * ans % MOD;
}
a = 1ll * a * a % MOD;
b >>= 1;
}
return ans;
};
// split into multiple "highways" of bad things
// m highways, choose 2*k from each one
vector<int> fact(2 * n + 1);
fact[0] = 1;
for (int i = 1; i <= 2 * n; ++i) {
fact[i] = 1ll * fact[i - 1] * i % MOD;
}
vector<int> inv(2 * n + 1);
inv[2 * n] = modpow(fact[2 * n], MOD - 2);
for (int i = 2 * n - 1; i >= 0; --i) {
inv[i] = 1ll * inv[i + 1] * (i + 1) % MOD;
}
vector<vector<int>> dp(m + 1, vector<int>(n + 1));
auto C = [&](int a, int b) {
return 1ll * (1ll * fact[a] * inv[a - 2 * b]) % MOD * modpow(modpow(2, b), MOD - 2) % MOD;
};
dp[0][0] = 1;
int sum = 0;
for (int i = 0; i < m; ++i) {
// number in current highway:
int cnt = (i < ((2 * n) % m) ? (2 * n) / m + 1 : (2 * n) / m);
for (int used = 0; used <= sum; ++used) {
for (int j = 0; j <= cnt >> 1; ++j) {
if (used + j <= n) {
(dp[i + 1][used + j] += (1ll * (1ll * dp[i][used] * C(cnt, j) % MOD) * inv[j] % MOD)) %= MOD;
}
}
}
sum += cnt;
}
int ans = C(2 * n, n);
int prod = 1;
for (int i = 1; i <= n; ++i) {
prod = 1ll * prod * (n - i + 1) % MOD;
(ans += 1ll * (1ll * (i & 1 ? -1 : 1) * prod * dp[m][i] % MOD) * C(2 * n - 2 * i, n - i) % MOD) %= MOD;
if (ans < 0) {
ans += MOD;
}
}
cout << 1ll * ans * modpow(2, n) % MOD;
return 0;
}
