#include<bits/stdc++.h>
using namespace std;

char s[2600];
vector<char> k;

int main()
{int i,j=0;
 while(1)
  {s[j]=getchar();
   if(s[j]=='@') break;
   j++;
  }
  
 for(i=0;i<j-1;i++)
   {if(s[i]=='(') k.push_back(s[i]);
    if(s[i]==')') k.pop_back();
   }
 if(k.size()) cout<<"NO";
 if(k.size()==0) cout<<"YES";
 return 0;
}