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