#include <bits/stdc++.h>
using namespace std;
template <class T>
inline T BM(T p, T e, T M) {
  long long int ret = 1;
  for (; e > 0; e >>= 1) {
    if (e & 1) ret = (ret * p) % M;
    p = (p * p) % M;
  }
  return (T)ret;
}
template <class T>
inline T gcd(T a, T b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
template <class T>
inline T MDINV(T a, T M) {
  return BM(a, M - 2, M);
}
template <class T>
inline T PW(T p, T e) {
  long long int ret = 1;
  for (; e > 0; e >>= 1) {
    if (e & 1) ret = (ret * p);
    p = (p * p);
  }
  return (T)ret;
}
template <class T>
string NTS(T Number) {
  stringstream ss;
  ss << Number;
  return ss.str();
}
template <class T>
T stringtonumber(const string &Text) {
  istringstream ss(Text);
  T result;
  return ss >> result ? result : 0;
}
template <class T>
bool ISLEFT(T a, T b, T c) {
  if (((a.first - b.first) * (b.second - c.second) -
       (b.first - c.first) * (a.second - b.second)) < 0.0)
    return 1;
  else
    return 0;
}
char ch[100000 + 2];
long long int ar[2009][2009];
int vis[2009][2009];
int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  scanf("%s", ch + 1);
  memset(ar, 0, sizeof ar);
  ar[0][0] = 1;
  memset(vis, 0, sizeof vis);
  for (int i = 1; i <= 2004; i++) {
    for (int j = 0; j <= 2004; j++) {
      ar[i][j] =
          ((j > 0 ? ar[i - 1][j - 1] : 0) + ar[i - 1][j + 1]) % 1000000007ll;
    }
  }
  int ans[2009];
  memset(ans, -1, sizeof ans);
  for (int j = 0; j <= 2004; j++) {
    int x = j;
    bool fl = 0;
    for (int k = 1; k <= m; k++) {
      if (ch[k] == ')' && x == 0) {
        fl = 1;
        break;
      } else if (ch[k] == '(')
        x++;
      else if (ch[k] == ')')
        x--;
    }
    if (fl == 0) {
      ans[j] = x;
    }
  }
  long long int res = 0;
  long long int ans1 = 0;
  for (int i = 0; i <= (n - m); i++) {
    for (int k = 0; k <= 2004; k++) {
      if (ans[k] != -1 && ans[k] <= (n - m - i)) {
        res = (res + (ar[i][k] * ar[n - m - i][ans[k]]) % 1000000007ll) %
              1000000007ll;
      }
    }
  }
  printf("%lld\n", res);
  return 0;
}
