#include <bits/stdc++.h>

using i64 = long long;

constexpr int N = 5e2 + 5, P = 1e9 + 7;

int n, k;
std::string s;
i64 dp[N][N][6];

bool isStar(int p) { return s[p] == '*' || s[p] == '?'; }
bool isPair(int l, int r) { return (s[l] == '(' || s[l] == '?') && (s[r] == ')' || s[r] == '?'); }

int main() {

    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    std::cin >> n >> k >> s; s = " " + s;
    
    for (int i = 1; i <= n; i++) if (isStar(i)) dp[i][i][0] = dp[i][i][5] = 1;
    for (int i = 1; i < n; i++) {
        if (isPair(i, i + 1)) dp[i][i + 1][1] = dp[i][i + 1][3] = 1;
        if (k >= 2 && isStar(i) && isStar(i + 1)) dp[i][i + 1][0] = dp[i][i + 1][5] = 1;
    }
    for (int len = 3; len <= n; len++)
        for (int l = 1; l + len - 1 <= n; l++) {
            int r = l + len - 1;
            if (len <= k) {
                dp[l][r][0] = 1;
                for (int i = l; i <= r; i++) if (!isStar(i)) {
                    dp[l][r][0] = 0;
                    break;
                }
            }   
            if (isPair(l, r)) dp[l][r][1] = (dp[l + 1][r - 1][0] + dp[l + 1][r - 1][2] + dp[l + 1][r - 1][3] + dp[l + 1][r - 1][4]) % P;
            dp[l][r][3] = dp[l][r][1];
            dp[l][r][5] = dp[l][r][0];
            for (int i = l; i < r; i++) {
                dp[l][r][2] = (dp[l][r][2] + dp[l][i][3] * dp[i + 1][r][0] % P) % P;
                dp[l][r][3] = (dp[l][r][3] + (dp[l][i][2] + dp[l][i][3]) * dp[i + 1][r][1] % P) % P;
                dp[l][r][4] = (dp[l][r][4] + (dp[l][i][4] + dp[l][i][5]) * dp[i + 1][r][1] % P) % P;
                dp[l][r][5] = (dp[l][r][5] + dp[l][i][4] * dp[i + 1][r][0] % P) % P;
            }
        }

    std::cout << dp[1][n][3] << "\n";

    return 0;
}