#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long power(long long first, unsigned long long second,
                unsigned long long m) {
  if (second == 0) return 1;
  long long p = power(first, second / 2, m) % m;
  p = (p * p) % m;
  return (second % 2 == 0) ? p : (first * p) % m;
}
long long modInverse(long long a, long long m) {
  { return power(a, m - 2, m); }
}
void __print(long long first) { cerr << first; }
void __print(float first) { cerr << first; }
void __print(double first) { cerr << first; }
void __print(long double first) { cerr << first; }
void __print(char first) { cerr << '\'' << first << '\''; }
void __print(const char *first) { cerr << '\"' << first << '\"'; }
void __print(const string &first) { cerr << '\"' << first << '\"'; }
void __print(bool first) { cerr << (first ? "true" : "false"); }
template <typename T, typename V>
void __print(const pair<T, V> &first) {
  cerr << '{';
  __print(first.first);
  cerr << ',';
  __print(first.second);
  cerr << '}';
}
template <typename T>
void __print(const T &first) {
  long long f = 0;
  cerr << '{';
  for (auto &i : first) cerr << (f++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\n"; }
template <typename T, typename... V>
void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v)) cerr << ", ";
  _print(v...);
}
long long sub(long long first, long long second) {
  return (first - second + 1000000007) % 1000000007;
}
long long mul(long long first, long long second) {
  return (first * second) % 1000000007;
}
long long add(long long first, long long second) {
  return (first + second) % 1000000007;
}
void solve() {
  long long n, k;
  cin >> n >> k;
  string s;
  cin >> s;
  k = n - k;
  long long dp[k + 1][k + 1];
  memset(dp, 0, sizeof dp);
  dp[0][0] = 1;
  for (long long j = 1; j <= k; j++) {
    for (long long i = 0; i <= k; i++) {
      if (i - 1 >= 0) {
        dp[i][j] += dp[i - 1][j - 1];
      }
      if (i + 1 <= k) {
        dp[i][j] += dp[i + 1][j - 1];
      }
      dp[i][j] %= 1000000007;
      dp[i][j] += 1000000007;
      dp[i][j] %= 1000000007;
    }
  }
  long long cnt = 0;
  long long minn = 1000000000000000008;
  for (auto it : s) {
    if (it == ')')
      cnt--;
    else
      cnt++;
    minn = min(minn, cnt);
  }
  long long ans = 0;
  for (long long i = max(0LL, -minn); i <= k; i++) {
    for (long long j = 0; j <= k; j++) {
      if (n - j - s.length() < 0 || i + cnt > k) continue;
      ans += (dp[i][j] * (dp[i + cnt][n - j - s.length()])) % 1000000007;
      ans %= 1000000007;
      ans += 1000000007;
      ans %= 1000000007;
    }
  }
  cout << ans << "\n";
}
signed main() {
  ios_base ::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
  solve();
  return 0;
}
