#include <bits/stdc++.h>
using namespace std;
const int module = 1e9 + 7;
inline long long mod(long long q) { return q % module; }
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n, m;
  string s;
  cin >> n >> m >> s;
  if (n % 2) {
    cout << "0\n";
    return 0;
  }
  int b = 0, min_b = 0;
  for (int i = 0; i < s.length(); ++i) {
    if (s[i] == '(')
      ++b;
    else
      --b;
    if (b < min_b) min_b = b;
  }
  const int CONST = 2100;
  vector<vector<long long> > d(n - m + 1, vector<long long>(n - m + 50, 0));
  d[0][0] = 1;
  for (int i = 0; i + 1 < d.size(); ++i) {
    for (int j = 0; j < d[i].size(); ++j) {
      if (j + 1 < d[i].size()) d[i + 1][j + 1] = mod(d[i + 1][j + 1] + d[i][j]);
      if (j > 0) d[i + 1][j - 1] = mod(d[i + 1][j - 1] + d[i][j]);
    }
  }
  long long ans = 0;
  for (int i = 0; i <= n - m; ++i) {
    for (int j = -min_b; j <= n - m; ++j) {
      if (abs(j + b) < d[0].size())
        ans = mod(ans + mod(d[i][j] * d[n - m - i][abs(j + b)]));
    }
  }
  cout << ans << "\n";
  return 0;
}
