#include <bits/stdc++.h>
using namespace std;
void Solve(int testcase);
long long int dp[2005][2005];
char s[100000 + 10];
int main() {
  int tc, t;
  tc = 1;
  for (t = 1; t <= tc; t++) Solve(t);
  return 0;
}
void Solve(int testcase) {
  long long int mod = 1000000007;
  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;
    }
  }
  int n, m;
  scanf("%d %d", &n, &m);
  scanf("%s", s + 1);
  int cnt = 0;
  int mn = m * 10;
  for (int i = 1; i <= m; i++) {
    if (s[i] == '(')
      cnt++;
    else
      cnt--;
    mn = min(mn, cnt);
  }
  long long int ans = 0;
  for (int i = 0; i <= n - m; i++) {
    for (int j = 0; j <= i; j++) {
      int l1 = n - m - i, diff = j + cnt;
      if (diff >= 0 && diff <= l1 && l1 >= 0 && j + mn >= 0) {
        ans = (ans + dp[i][j] * dp[l1][diff]) % mod;
      }
    }
  }
  printf("%lld\n", ans);
}
