#include <stdio.h>
int main(){
int n;
scanf("%d",&n);
switch(n){
case 0 ... 3:
printf("infant");
break;
case 4 ... 12:
printf("child");
break;
case 13 ... 18:
printf("youngster");
break;
case 19 ... 25:
printf("youth");
}
   return 0;
}