#include <bits/stdc++.h> 

using i64 = long long; 
using u64 = unsigned long long; 
using u32 = unsigned; 

using u128 = unsigned __int128; 
using i128 = __int128; 

void solve() {
	int N, K; std::cin >> N >> K;
	std::string S; std::cin >> S;
	
	std::vector<int> ans(N + 1);
	std::stack<int> st;

	for(int i = 0; i < N; i ++) {
		if(S[i] == '(') st.push(i + 1);
		else {
			ans[st.top()] = i + 1;
			ans[i + 1] = st.top();
			st.pop();
		}
	}

	std::cout << ans[K] << "\n";
} 

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

	int T = 1; 
	//std::cin >> T; 

	while (T--) { 
		solve(); 
	} 
	return 0; 
}