#include<iostream>
using namespave std;
int main(){
    int n;
    cin>>n;
    if(n<0){
        cout<<"invalide input "<< endl;
        
    }
    else if (n>=18){
        cout<<"eligible"<<endl;
        
    }
    else{
        cout<<"not eligible"<<endl;
    }
    return 0;
}