BK1

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

constexpr int N = 5e3 + 5;
constexpr ll mod = 1e9 + 7;
int n, k, x;
string s;
int dp[N][N];

void Read()
{
    cin >> k >> s;
    n = s.size();
    s = " " + s;
}

int f(int i, int sum)
{
    if (i == n + 1)
        return sum == 0;

    int &ans = dp[i][sum];

    if (ans != -1)
        return ans;

    ans = 0;
    ans = f(i + 1, sum) % mod;

    if (sum + (s[i] == '(' ? 1 : -1) <= x && sum + (s[i] == '(' ? 1 : -1) >= 0)
        (ans += f(i + 1, sum + (s[i] == '(' ? 1 : -1)) % mod) % mod;

    return ans;
}

int g(int v)
{
    x = v;
    memset(dp, -1, sizeof dp);
    return f(1, 0);
}

void Solve()
{
    cout << ((g(k) - g(k - 1)) % mod + mod) % mod;
}

int32_t main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    Read();
    Solve();
}