#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;
}

#include<bits/stdc++.h> using namespace std; int main() { int sb; cin>>sb; if(sb>=0&&sb<4) { cout<<"infant"; } else { if(sb>=4&&sb<13) { cout<<"child"; } else { if(sb>=13&&sb<19) { cout<<"youngster"; } else { if(sb<26) { cout<<"youth"; } } } } return 0; }