#include <bits/stdc++.h>
using namespace std;
const int64_t MOD = 1000 * 1000 * 1000 + 7;
int main() {
  int n, m;
  int64_t mn = MOD, b = 0;
  string s;
  cin >> n >> m;
  cin >> s;
  vector<vector<int64_t>> dp(n - m + 1, vector<int64_t>(n - m + 1, 0));
  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]) % MOD;
    }
  }
  for (int i = 0; i < m; i++) {
    if (s[i] == '(') {
      b++;
    } else {
      b--;
    }
    mn = min(mn, b);
  }
  int64_t ans = 0;
  for (int i = 0; i <= n - m; i++) {
    for (int j = 0; j <= i; j++) {
      if (0 <= mn + j && j + b <= n - m) {
        ans = (ans + (dp[i][j] * dp[n - m - i][j + b]) % MOD) % MOD;
      }
    }
  }
  cout << ans;
  return 0;
}
