#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pl;
typedef pair<int,int> pii;
typedef tuple<int,int,int> tpl;
#define all(a) a.begin(), a.end()
#define filter(a) a.erase(unique(all(a)), a.end())
const int MOD = 1e9 + 7;
int fact[4040], ifac[4040], grCount[4040], getGr[4040];
int dp[2020][2020];
int add (int a, int b) { return a + b - (a + b < MOD ? 0 : MOD); }
int sub (int a, int b) { return a - b + (a - b >= 0 ? 0 : MOD); }
int mul (int a, int b) { return 1LL * a * b % MOD; }
int binpow (int a, int b = MOD - 2) {
int ans = 1;
for (; b; b >>= 1) {
if (b & 1) ans = mul(ans, a);
a = mul(a, a);
}
return ans;
}
int C (int n, int k) {
int ans = mul(fact[n], ifac[k]);
return mul(ans, ifac[n - k]);
}
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
/// pre-calculate combinatorics
fact[0] = 1;
for (int i = 1; i <= 2000; i++) fact[i] = mul(fact[i - 1], i);
ifac[2000] = binpow(fact[2000]);
for (int i = 2000; i >= 1; i--) ifac[i - 1] = mul(ifac[i], i);
/// read input & pre-calculations
int n, m, pre = 0; cin >> n >> m;
for (int i = 0; i <= 2 * n; i++) getGr[i] = -1;
for (int i = 0; i < m; i++) {
grCount[i] = (2 * n) / m + (i < (2 * n) % m);
pre += grCount[i], getGr[pre] = i;
}
/// run DP
dp[0][0] = 1;
for (int i = 0; i <= n; i++) {
for (int j = 0; j <= n && 2 * i + j <= 2 * n; j++) {
int cur = 2 * i + j;
if (getGr[cur] == -1) continue;
int need = grCount[getGr[cur]];
// cout << "state " << i << " " << j << " group " << getGr[cur] << "\n";
for (int x = 0; x <= min(i, need); x++) {
int y = need - x;
if (y <= j) {
int contrib = mul(fact[need], mul(mul(C(i, x), binpow(2, x)), C(j, y)));
dp[i][j] = add(dp[i][j], mul(dp[i - x][j + x - y], contrib));
}
}
}
}
cout << dp[n][0];
return 0;
}
