#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#define pb push_back
#define F first
#define S second
#define ld long double
#define all(a) a.begin(),a.end()
#define pii pair <int,int>
#define int long long
#define PII pair<pii , pii>
#define sz(v) (int)v.size()
#define rep(i , a , b) for(int i=a;i <= (b);i++)
#define per(i , a , b) for(int i=a;i >= (b);i--)
#define deb(x) cout <<#x << " : " << x << "\n" ;
using namespace std ;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int maxn = 4000+10 + 10, inf = 1e9+10 , mod = 1e9 + 7 ;
int f[maxn], inv[maxn] , dp[maxn][maxn] ;
int po(int a, int b){
if(b==0)return 1 ;
int v =po(a,b/2) ;
v = v*v % mod ;
if(b&1) v= v*a % mod ;
return v ;
}
int c(int n , int k){
if(n < k || k < 0)return 0 ;
return f[n]*inv[k]%mod*inv[n-k]%mod ;
}
int t[maxn] ;
signed main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
f[0] = 1;
rep(i , 1,maxn-1)f[i] = f[i-1] *i % mod ;
inv[maxn-1] = po(f[maxn-1] , mod-2) ;
per(i , maxn-2 ,0){
inv[i] = inv[i+1] * (i+1) % mod ;
}
int n , m;
cin >> n >> m ;
rep(i , 1, 2*n){
t[(i-1)%m]++;
}
dp[0][0] = 1;
rep(i , 1 ,m){
rep(j ,0 ,n){
rep(k , 0 , min(t[i-1] , j)){
dp[i][j-k+(t[i-1] - k)] = (dp[i][j-k+(t[i-1]-k)] + dp[i-1][j] * c(t[i-1] , k)%mod * f[k]%mod * c(j , k)%mod)%mod ;
}
}
}
int ans = dp[m][0] * po(2,n)%mod *f[n]%mod;
cout << ans<< "\n";
return 0 ;
}
/*
*/
