tj\

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

int main()
{
    string a;
    cin>>a;
    if(a[0]<='9')
    {
        cout<<"no";
        return 0;
    }
    for(int i = 1;i<a.size();i++)
        if(!((a[i]<='9'&&a[i]>='0')||(a[i]>='a'&&a[i]<='z')||(a[i]>='A'&&a[i]<='Z')))
        {
            cout<<"no";
            return 0;
        }
    cout<<"yes";
}