#include <bits/stdc++.h>
using namespace std;
template <class T>
inline T gcd(T a, T b) {
  return (b) == 0 ? (a) : gcd((b), ((a) % (b)));
}
template <class T>
inline T lcm(T a, T b) {
  return ((a) / gcd((a), (b)) * (b));
}
template <class T>
inline T BigMod(T Base, T power, T M = 1000000007) {
  if (power == 0) return 1;
  if (power & 1)
    return ((Base % M) * (BigMod(Base, power - 1, M) % M)) % M;
  else {
    T y = BigMod(Base, power / 2, M) % M;
    return (y * y) % M;
  }
}
template <class T>
inline T ModInv(T A, T M = 1000000007) {
  return BigMod(A, M - 2, M);
}
int fx[] = {-1, +0, +1, +0, +1, +1, -1, -1, +0};
int fy[] = {+0, -1, +0, +1, +1, -1, +1, -1, +0};
int day[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
int n, m;
string s;
int mn, mx;
long long dp[2001][2001][2];
long long giveres(int pos, int baki, int flag) {
  if (baki > 2000 || baki < 0) return 0;
  if (pos == n - m + 1) {
    if (baki == 0 && flag == 1)
      return 1ll;
    else
      return 0;
  }
  long long &ret = dp[pos][baki][flag];
  if (ret != -1) return ret;
  ret = 0;
  if (flag == 0 && baki >= mn) {
    ret = giveres(pos + 1, baki + mx - mn, 1);
  }
  ret = (ret +
         (giveres(pos + 1, baki - 1, flag) + giveres(pos + 1, baki + 1, flag)) %
             1000000007) %
        1000000007;
  if (ret >= 1000000007) ret %= 1000000007;
  return ret;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cin >> n >> m >> s;
  int cc = 0;
  for (int i = 0; i < m; i++) {
    if (s[i] == ')') {
      if (cc)
        cc--;
      else
        mn++;
    } else {
      cc++;
    }
  }
  cc = 0;
  for (int i = m - 1; i >= 0; i--) {
    if (s[i] == '(') {
      if (cc)
        cc--;
      else
        mx++;
    } else
      cc++;
  }
  memset(dp, -1, sizeof(dp));
  cout << giveres(0, 0, 0) << endl;
  return 0;
}
