#include <bits/stdc++.h>
using namespace std;
char str[100001];
long long ans, dp[2200][2200];
long long MOD = 1000000007;
int n, m;
int main() {
  scanf("%d%d%s", &n, &m, str);
  dp[0][0] = 1LL;
  for (int i = 1; i <= 2100; 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 diff = 0;
  int start = 0;
  for (int i = 0; i < m; i++) {
    if (str[i] == '(')
      diff++;
    else
      diff--;
    if (diff < 0) start = max(start, -diff);
  }
  ans = 0;
  for (int i = 0; i <= n - m; i++) {
    int rest = n - m - i;
    for (int j = start; j <= i; j++) {
      if (j <= rest - diff) {
        ans += (dp[i][j] * dp[rest][j + diff]) % MOD;
        ans %= MOD;
      }
    }
  }
  printf("%lld\n", ans);
  return 0;
}
