#include <bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
const double eps = 1e-8;
const int mod = 1000000007;
const double pi = acos(-1.0);
inline void gn(long long& x) {
  int sg = 1;
  char c;
  while (((c = getchar()) < '0' || c > '9') && c != '-')
    ;
  c == '-' ? (sg = -1, x = 0) : (x = c - '0');
  while ((c = getchar()) >= '0' && c <= '9') x = x * 10 + c - '0';
  x *= sg;
}
inline void gn(int& x) {
  long long t;
  gn(t);
  x = t;
}
inline void gn(unsigned long long& x) {
  long long t;
  gn(t);
  x = t;
}
long long gcd(long long a, long long b) { return a ? gcd(b % a, a) : b; }
long long powmod(long long a, long long x, long long mod) {
  long long t = 1ll;
  while (x) {
    if (x & 1) t = t * a % mod;
    a = a * a % mod;
    x >>= 1;
  }
  return t;
}
const int maxn = 2222;
long long dp[maxn][maxn];
void add(long long& a, long long b) {
  a += b;
  if (a > mod) a -= mod;
}
int main() {
  int n, m;
  string s;
  cin >> n >> m >> s;
  int tt = 0;
  int dif = 0;
  for (int i = (0); i <= (m - 1); i++) {
    if (s[i] == ')')
      tt--;
    else
      tt++;
    dif = min(dif, tt);
  }
  dp[0][0] = 1;
  for (int i = (1); i <= (2000); 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]);
    }
  }
  long long ans = 0;
  for (int i = (0); i <= (n - m); i++) {
    for (int j = (max(0, -dif)); j <= (i); j++) {
      if (j + tt <= n - m - i)
        add(ans, dp[i][j] * dp[n - m - i][abs(tt + j)] % mod);
    }
  }
  cout << ans << endl;
  return 0;
}
