#include <iostream>
#include <string>
#include<cctype>
using namespace std;
int main(){
    string s,clean="";
    getline(cin,s);
    if(s.length()>100){
        cout<<"INVALID INPUT";
        return 0;
    }
    for(char c:s){
        if(isalnum(c)){
            clean+=tolower(c);
        }
        else if(c!='-'||c=='.'){
            cout<<"INVALID INPUT";
            return 0;
        }
        |++;r--;
    }
    
    cout<<"YES";
    return 0;
}