#include <bits/stdc++.h>
using namespace std;
const long long md = 1e9 + 7;
long long n, m, c[1010][1010], dp[1010][1010][1 << 2], cc[1010];
int main() {
  cin >> n >> m;
  for (int i = 0; i <= n; i++) {
    for (int j = 0; j <= i; j++) {
      if (j == 0) {
        c[i][j] = 1;
      } else {
        c[i][j] = c[i - 1][j - 1] + c[i - 1][j];
        c[i][j] %= md;
      }
    }
  }
  dp[0][0][0] = 1;
  for (int i = 1; i <= n; i++) {
    for (int j = 0; j <= i; j++) {
      for (int k = 0; k < 4; k++) {
        if (i > 1 && j > 0 && (k & 1) == 0) {
          dp[i][j][k >> 1] += dp[i - 1][j - 1][k];
          dp[i][j][k >> 1] %= md;
        }
        if (i < n && j > 0) {
          dp[i][j][(k >> 1) | 2] += dp[i - 1][j - 1][k];
          dp[i][j][(k >> 1) | 2] %= md;
        }
        dp[i][j][k >> 1] += dp[i - 1][j][k];
        dp[i][j][k >> 1] %= md;
      }
    }
  }
  long long nw = 1;
  for (int i = n; i >= 0; i--) {
    cc[i] = (dp[n][i][0] + dp[n][i][1]) * nw % md;
    nw *= (n - i + 1);
    nw %= md;
  }
  for (int i = n; i >= m; i--) {
    for (int j = n; j > i; j--) {
      cc[i] -= cc[j] * c[j][i] % md;
      cc[i] += md;
      cc[i] %= md;
    }
  }
  cout << cc[m] << endl;
  return 0;
}
