AC

#include<iostream>
using namespace std;
int main(){
string a;
int i = 0,top = 0,tmp = 0;
cin >> a;
while(a[i] != '@'){
if(a[i] == '(')top++;
if(a[i] == ')')top--;
if(top < 0)tmp = 1;
i++;
}
if(top != 0)tmp = 1;
if(tmp == 0)cout << "YES";
else cout << "NO";
return 0;
}