T96987进不了讨论区，求调QwQ

#include<bits/stdc++.h>
using namespace std;
string c;
stack<char> s;
int main(){
    cin>>c;
    int num=0;
    while(1){
    	if(c[num]=='@')
    	    break;
    	else if(c[num]=='('||c[num]=='['||c[num]=='{')
    		s.push(c[num]);
		else if((!s.empty()&&s.top()=='('&&c[num]==')')||(!s.empty()&&s.top()=='['&&c[num]==']')||(!s.empty()&&s.top()=='{'&&c[num]=='}'));
			s.pop();
		num++;
	}
	if(s.empty())
	    cout<<"YES";
	else
	    cout<<"NO";
    return 0;
}