#include <bits/stdc++.h>
using namespace std;
int main()
{
    char c;
    cin >>c;
   if((c>='a'&&c<='z')||(c>='A'&&c<='Z')||('1'<=c&&c<='9'))
    {
        cout<<"YES";
    }
    else
    {
        cout<<"NO";
    }
    return 0;

}