#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
const int MAXN = 2016;
int n, m;
string s;
int dp[MAXN][MAXN];
void add(int &x, int y) {
  x += y;
  if (x >= MOD) x -= MOD;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cin >> n >> m >> s;
  int balance = 0, minbal = 0;
  for (int i = 0; i < (int)s.size(); ++i) {
    if (s[i] == '(')
      ++balance;
    else
      --balance;
    minbal = min(minbal, balance);
  }
  dp[0][0] = 1;
  for (int i = 1; i < MAXN; ++i) {
    for (int j = 0; j <= i; ++j) {
      if (j > 0) add(dp[i][j], dp[i - 1][j - 1]);
      add(dp[i][j], dp[i - 1][j + 1]);
    }
  }
  int res = 0;
  for (int lenp = 0; lenp <= n - m; ++lenp) {
    for (int bal = max(0, -minbal); bal <= lenp; ++bal) {
      if (bal + balance <= n - m)
        add(res, dp[lenp][bal] * 1ll * dp[n - m - lenp][bal + balance] % MOD);
    }
  }
  cout << res << '\n';
  return 0;
}
