#include <bits/stdc++.h>
using namespace std;
long long dp[2005][2005];
const int mod = 1e9 + 7;
int main() {
  int n, m;
  char s[100005];
  dp[0][0] = 1;
  for (int i = 1; i <= 2000; 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;
    }
  }
  while (~scanf("%d%d", &n, &m)) {
    scanf("%s", s);
    int l = 0, r = 0, sum = 0;
    for (int i = 0; i < m; i++) {
      if (s[i] == '(')
        sum++;
      else
        sum--;
      l = min(l, sum);
    }
    l = -l;
    sum = 0;
    for (int i = m - 1; i >= 0; i--) {
      if (s[i] == ')')
        sum++;
      else
        sum--;
      r = min(r, sum);
    }
    r = -r;
    long long ans = 0;
    for (int i = 0; i <= n - m; i++) {
      for (int j = 0; j <= n - m; j++) {
        int len = n - m - i;
        int j2 = j - sum;
        if (j2 <= n - m && i >= l && j2 >= r) {
          ans = (ans + dp[i][j] * dp[len][j2]) % mod;
        }
      }
    }
    printf("%lld\n", ans);
  }
  return 0;
}
