#include <bits/stdc++.h>
using namespace std;
const int N = 2e3 + 5;
const long long mod = 1e9 + 7;
long long dp[N][N];
char s[100000 + 5];
int main() {
  int m, n;
  scanf("%d%d%s", &n, &m, s + 1);
  dp[0][0] = 1;
  for (int i = 1; i <= n - m; ++i) {
    for (int j = 0; j <= i; ++j) {
      if (!j)
        dp[i][j] = dp[i - 1][j + 1];
      else
        dp[i][j] = (dp[i - 1][j - 1] + dp[i - 1][j + 1]) % mod;
    }
  }
  int cnt = 0, d = m + 1;
  for (int i = 1; i <= m; ++i) {
    if (s[i] == '(')
      ++cnt;
    else
      --cnt;
    d = min(d, cnt);
  }
  long long ans = 0;
  for (int i = 0; i <= n - m; ++i) {
    for (int j = 0; j <= i; ++j) {
      if (-d <= j && cnt + j <= n - m - i)
        ans = (ans + dp[i][j] * dp[n - m - i][cnt + j]) % mod;
    }
  }
  printf("%I64d\n", ans);
  return 0;
}
