#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
const int INF = 0x3f3f3f3f;
const int MAXN = 1e5 + 5;
const int MAXM = 2005;
int n, m, cnt, num;
long long ans, dp[MAXM][MAXM];
char s[MAXN];
int main(int argc, char const *argv[]) {
  scanf("%d%d", &n, &m);
  scanf("%s", s);
  for (int i = 0; i < m; ++i) {
    if (s[i] == '(')
      cnt++;
    else
      cnt--;
    num = min(num, cnt);
  }
  dp[0][0] = 1;
  for (int i = 1; i <= n - m; ++i)
    for (int j = 0; j <= i; ++j) {
      dp[i][j] = 0;
      if (j > 0) dp[i][j] += dp[i - 1][j - 1];
      if (j < i) dp[i][j] += dp[i - 1][j + 1];
      dp[i][j] %= MOD;
    }
  for (int i = 0; i <= n - m; ++i)
    for (int j = -num; j <= i; ++j) {
      if (j + cnt < MAXM) ans += dp[i][j] * dp[n - m - i][j + cnt] % MOD;
      ans %= MOD;
    }
  printf("%lld\n", ans);
  return 0;
}
