#include<stdio.h> int main() { int n; scanf("%d",&n); switch(n) { case 0: case 1: case 2: case 3:printf("infant");break; case 4: case 5: case 6: case 7: case 8: case 9: case 10: case 11: case 12:printf("child");break; case 13: case 14: case 15: case 16: case 17: case 18:printf("youngster");break; case 19: case 20: case 21: case 22: case 23: case 24: case 25:printf("youth");break; } return 0; }