#include <bits/stdc++.h>
const long long Inf = 2e9;
const long long Inf64 = 1e18;
const long long MaxN = 2e3 + 100;
const long long md = 1e9 + 7;
using namespace std;
long long dp[MaxN][MaxN];
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie();
  cout.tie();
  cerr.tie();
  long long N, M;
  cin >> N >> M;
  dp[0][0] = 1;
  long long r = N - M;
  for (int i = 0; i <= r; i++) {
    for (int j = 0; j <= i; j++) {
      dp[i + 1][j + 1] += dp[i][j];
      if (j > 0) dp[i + 1][j - 1] += dp[i][j];
      if (dp[i + 1][j + 1] >= md) dp[i + 1][j + 1] -= md;
      if (j > 0 && dp[i + 1][j - 1] >= md) dp[i + 1][j - 1] -= md;
    }
  }
  string s;
  cin >> s;
  long long b = 0, a = 0;
  for (int i = 0; i < M; i++) {
    if (s[i] == '(') {
      ++b;
    } else {
      --b;
      a = max(a, -b);
    }
  }
  long long Ans = 0;
  for (int i = 0; i <= r; i++) {
    for (int j = 0; j <= i; j++) {
      if (j < a) continue;
      long long c = j + b;
      if (c <= r) Ans += (dp[i][j] * dp[r - i][c]) % md;
      if (Ans >= md) Ans -= md;
    }
  }
  cout << Ans;
  return 0;
}
