#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin>>n;
    if(n>=0&&n<=3) cout<<"infant";
    if(n>=4&&n<=12) cout<<"child";
    if(n>=13&&n<=18) cout<<"youngster";
    if(n>=19&&n<=25) cout<<"youth";
    return 0;
}