#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
const int M = 2005;
const int MOD = 1e9 + 7;
char s[N];
int dp[M][M];
void addmod(int& a, int b) {
  a += b;
  if (a >= MOD) a -= MOD;
}
int main() {
  int n, m;
  scanf("%d%d%s", &n, &m, s);
  int cnt = 0, mn = 1e9;
  for (int i = 0; i < m; i++) {
    s[i] == '(' ? cnt++ : cnt--;
    mn = min(mn, cnt);
  }
  dp[0][0] = 1;
  for (int i = 0; i <= n - m; i++) {
    for (int j = 0; j <= i; j++) {
      addmod(dp[i + 1][j + 1], dp[i][j]);
      if (j > 0) addmod(dp[i + 1][j - 1], dp[i][j]);
    }
  }
  int ans = 0;
  for (int i = 0; i <= n - m; i++) {
    for (int j = 0; j <= i; j++) {
      if (j + mn < 0) continue;
      if (j + cnt > n - m - i) continue;
      addmod(ans, (long long)dp[i][j] * dp[n - m - i][j + cnt] % MOD);
    }
  }
  printf("%d\n", ans);
  return 0;
}
