#include <bits/stdc++.h>
using namespace std;
char s[100005];
int mod = 1000000007;
long long a[2005][4005];
long long b[2005][4005];
int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  scanf("%s", s);
  int mn = 0;
  int sum = 0;
  for (int i = 0; i < m; i++) {
    if (s[i] == '(')
      sum++;
    else
      sum--;
    mn = min(sum, mn);
  }
  n -= m;
  if (sum > n || -mn > n) {
    printf("0\n");
    return 0;
  }
  mn = -mn;
  a[0][0] = 1;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j <= i; j++) {
      if (a[i][j] > 0) {
        a[i + 1][j + 1] += a[i][j];
        if (a[i + 1][j + 1] >= mod) a[i + 1][j + 1] -= mod;
        if (j > 0) {
          a[i + 1][j - 1] += a[i][j];
          if (a[i + 1][j - 1] >= mod) a[i + 1][j - 1] -= mod;
        }
      }
    }
  }
  for (int i = 0; i <= n; i++) {
    for (int j = mn; j <= n; j++) {
      if (j + sum <= n - i) {
        b[n - i][j + sum] += a[i][j];
        if (b[n - i][j + sum] >= mod) b[n - i][j + sum] -= mod;
      }
    }
  }
  for (int i = n; i > 0; i--) {
    for (int j = 0; j <= i; j++) {
      if (b[i][j] > 0) {
        b[i - 1][j + 1] += b[i][j];
        if (b[i - 1][j + 1] >= mod) b[i - 1][j + 1] -= mod;
        if (j > 0) {
          b[i - 1][j - 1] += b[i][j];
          if (b[i - 1][j - 1] >= mod) b[i - 1][j - 1] -= mod;
        }
      }
    }
  }
  printf("%I64d\n", b[0][0]);
  return 0;
}
