#include <bits/stdc++.h>
#define rep(a, b, c) for (int a = (b); (a) <= (c); a++)
#define per(a, b, c) for (int a = (b); (a) >= (c); a--)
#define nl '\n'
#define ioi exit(0);
const int mod = (int)1e9 + 7;
const int N = (int)1e4;
using namespace std;
void add(int &x, int y) {
x += y;
if (x >= mod) x -= mod;
}
int sum(int x, int y) {
add(x, y);
return x;
}
int n, m;
int dp[3005][3005];
int main() {
#ifdef IOI
freopen ("in.txt", "r", stdin);
freopen ("slow.out", "w", stdout);
#endif
cin >> n >> m;
/* memset(dp, -1, sizeof(dp));
int ans = sum(calc(), -1);
cout << ans << nl; */
dp[0][m] = 1;
rep(i, 0, n - 1) {
rep(j, 0, m) {
add(dp[i + 1][j], dp[i][j]);
if (j > 0) {
add(dp[i + 1][j - 1], dp[i][j] * 1ll * 4 * j % mod);
add(dp[i + 2][j - 1], dp[i][j] * 1ll * (n - i - 1) * j % mod)
}
if (j > 1) add(dp[i + 1][j - 2], dp[i][j] * 1ll * (j * (j - 1) / 2) % mod);
}
}
int ans = -1;
rep(i, 0, m) add(ans, dp[n][i]);
if (ans < 0) ans += mod;
cout << ans;
ioi
}
/*
5116 0
3720 1
450 2
*/
Compilation message
tents.cpp: In function 'int main()':
tents.cpp:41:7: error: expected ';' before '}' token
}
^
