#include<iostream> #include<algorithm> #include<stack> using namespace std; using lint=int64_t; int main() { int N,K; string S; cin >> N >> K; cin >> S; K--; int ans=-1; stack<int> s; for(int i=0;i<S.size();i++) { if(S[i]=='(') s.push(i); else { if(i==K) ans=s.top(); else { if(s.top()==K) ans=i; s.pop(); } } if(ans!=-1) break; } cout << ans+1 << endl; return 0; }