#include <iostream>
#include <string>

using namespace std;

string a;

int main(){
    int ok=0,k=1;
    getline(cin,a);
    if(a[0]>='A' && a[0]<='Z'){
        for(int i=1;i<=a.size();++i){
            if(a[i]>='A' && a[i]<='Z'){
                if(a[i+1]<'A' || (a[i+1]>'Z' && a[i+1]<'a') || a[i+1]>'z'){
                    ok=1;
                }
                ++k;
            }
        }
    }
    else{
        cout <<"NO";
        ok=2;
    }
    if(ok==1){
        cout <<"NO";
    }
    if(ok==0 && k>1){
        cout <<"YES";
    }
    if(ok==0 && k<=1){
        cout <<"NO";
    }
    return 0;
}