#include <bits/stdc++.h>
using namespace std;
const int INF = 2e9;
const int maxn = 2e5;
const int mod = 1e9 + 7;
long long dp[2010][2010] = {0};
void init(int k) {
  dp[0][0] = 1;
  for (int i = 1; i <= k; 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;
    }
  }
}
int main() {
  int n, m;
  cin >> n >> m;
  char s[maxn];
  cin >> s;
  init(n - m);
  int pre = -INF, suf, sum = 0;
  for (int i = 0; i < m; i++) {
    if (s[i] == ')')
      sum++;
    else
      sum--;
    pre = max(pre, sum);
  }
  sum = 0;
  for (int i = m - 1; i >= 0; i--) {
    if (s[i] == '(')
      sum++;
    else
      --sum;
  }
  long long ans = 0;
  for (int i = 0; i <= n - m; i++)
    for (int j = 0; j <= n - m; j++) {
      int k = j + sum;
      if (j >= pre && k <= n - m) {
        ans += dp[i][j] * dp[n - m - i][k] % mod;
        ans %= mod;
      }
    }
  cout << ans << endl;
  return 0;
}
