#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 100010;
const int MAX_M = 2010;
const long long mod = (long long)(1e9) + 7;
int n, m;
char s[MAX_N];
long long dp[MAX_M][MAX_M];
int main() {
  while (~scanf("%d%d", &n, &m)) {
    scanf("%s", s);
    int Min = MAX_N, tmp = 0;
    for (int i = 0; i < m; ++i) {
      if (s[i] == '(')
        tmp++;
      else
        tmp--;
      Min = min(Min, tmp);
    }
    int diff = n - m;
    if ((n & 1) || tmp > diff || -tmp > diff) {
      printf("0\n");
      continue;
    }
    memset(dp, 0, sizeof(dp));
    dp[0][0] = 1;
    dp[1][0] = 0, dp[1][1] = 1;
    for (int i = 2; i <= diff; ++i) {
      for (int j = 0; j <= i; ++j) {
        if (j == 0)
          dp[i][j] = dp[i - 1][j + 1];
        else
          dp[i][j] = dp[i - 1][j - 1] + dp[i - 1][j + 1];
        dp[i][j] %= mod;
      }
    }
    long long ans = 0;
    int st = 0;
    if (Min < 0) st = -Min;
    for (int i = st; i <= diff; ++i) {
      for (int j = st; j <= i; ++j) {
        ans = (ans + dp[i][j] * dp[n - i - m][j + tmp] % mod) % mod;
      }
    }
    printf("%I64d\n", ans);
  }
  return 0;
}
