#include <iostream>
using namespace std;
char a[300];
int main()
{
   scanf("%s", &a);
   int i = 0, p = 0, m = 0, n = 0;
   while (a[i] != '@')
   {
   	if (a[i] == '(')
   	{
   		m++;
   		if (p == 0)
   		{
   			p++;
   		}
   	}
   	if (a[i] == ')')
   	{
   		n++;
   		if (p != 0)
   		{
   			p--;
   		}
   		else
   		{
   			cout << "NO";
   			return 0;
   		}
   	}
   	i++;
   }
   if (m == n && p == 0)
   {
   	cout << "YES";
   }
   else
   {
   	cout << "NO";
   }
   return 0;
}