#include <bits/stdc++.h>
using namespace std;
const int maxn = 2e3 + 10;
const int maxm = 1e5 + 10;
const int inf = 1e9;
const int mod = 1e9 + 7;
int getint() {
  char c;
  while ((c = getchar()) && !(c >= '0' && c <= '9') && c != '-')
    ;
  int ret = c - '0', sgn = 0;
  if (c == '-') sgn = 1, ret = 0;
  while ((c = getchar()) && c >= '0' && c <= '9') ret = ret * 10 + c - '0';
  if (sgn) ret = -ret;
  return ret;
}
long long dp[maxn][maxn];
char s[maxm];
int main() {
  int n, m;
  while (cin >> n >> m) {
    scanf("%s", s);
    memset(dp, 0, sizeof(dp));
    dp[0][0] = 1;
    for (int i = 1; i < maxn; i++) {
      for (int j = 0; j <= i; j++) {
        dp[i][j] = 0;
        if (j) dp[i][j] = (dp[i][j] + dp[i - 1][j - 1]) % mod;
        if (j < i) dp[i][j] = (dp[i][j] + dp[i - 1][j + 1]) % mod;
      }
    }
    int mib = 0, a = 0;
    for (int i = 0; i < m; i++) {
      if (s[i] == '(')
        a++;
      else
        a--;
      mib = min(mib, a);
    }
    mib = -mib;
    int lenp = n - m;
    long long ans = 0;
    for (int i = 0; i <= lenp; i++) {
      for (int j = mib; j <= i; j++) {
        if (n - m - i < j + a) continue;
        ans = (ans + dp[i][j] * dp[n - m - i][j + a] % mod) % mod;
      }
    }
    cout << ans << endl;
  }
  return 0;
}
