#include <bits/stdc++.h>
using namespace std;
long long int dp[3000][3000];
int main() {
  long long int n, m, ans = 0;
  cin >> n >> m;
  string s;
  cin >> s;
  long long int mb = 10000000000, b = 0;
  for (int i = 0; i < m; i++) {
    if (s[i] == '(')
      b++;
    else
      b--;
    mb = min(mb, b);
  }
  dp[0][0] = 1;
  for (int i = 1; i <= n - m; i++) {
    dp[i][0] = dp[i - 1][1];
    for (int j = 1; j <= i; j++) {
      dp[i][j] = dp[i - 1][j - 1] + dp[i - 1][j + 1];
      dp[i][j] %= 1000000007;
    }
  }
  for (int i = 0; i < n - m + 1; i++) {
    for (int j = 0; j < i + 1; j++) {
      if (j >= -mb) {
        if (j + b >= 0 && j + b <= n - m)
          ans += dp[i][j] * dp[n - m - i][j + b] % 1000000007;
        ans %= 1000000007;
      }
    }
  }
  cout << ans << endl;
}
