#include<bits/stdc++.h>
using namespace std;
int top=0;
char n;
int main(){
    while(cin>>n){
    	if(n=='@'){
            if(top==0)
                cout<<"YES";
            else
                cout<<"NO";
        }
    	if(n=='(')
    		top++;
    	if(n==')')
    		top--;
    	if(top<0){
    		cout<<"NO";
    		return 0;
		}
	}
}