#include <bits/stdc++.h>
using namespace std;
long long dp[2005][2005];
int main() {
  long long n, m;
  cin >> n >> m;
  string second;
  cin >> second;
  int k = n - m;
  dp[0][0] = 1;
  for (int i = 1; i <= k; i++) {
    for (int j = 0; j <= i; j++) {
      if (j > 0) dp[i][j] = dp[i - 1][j - 1];
      if (j < i) dp[i][j] = (dp[i][j] + dp[i - 1][j + 1]) % 1000000007;
    }
  }
  int st = 0, en = 0;
  for (int i = 0; i < m; i++) {
    if (second[i] == '(')
      en++;
    else
      en--;
    st = min(st, en);
  }
  st *= -1;
  long long ans = 0;
  for (int i1 = 0; i1 <= k; i1++) {
    for (int j1 = st; j1 <= i1; j1++) {
      int i2 = k - i1;
      int j2 = j1 + en;
      if (i2 < j2) continue;
      long long temp = (dp[i1][j1] * dp[i2][j2]) % 1000000007;
      ans = (ans + temp) % 1000000007;
    }
  }
  cout << ans << endl;
}
