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

#include<stdio.h> int main() { int n;

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

}

#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;
}

#include<stdio.h>int main(){ int n; scanf("%d",&n); if(n<=3){ printf("infant"); }else{ if(n<=12){ printf("child"); }else{ if(n<=18){ printf("youngster"); }else{ printf("youth"); } } } return 0;}

#include <stdio.h>
int main()
{
    int a;
    scanf("%d",&a);
    if (a<=3)printf("infant");
    else if(a<=12)printf("child");
    else if(a<18)printf("youngster");
    else printf("youth");
    return 0;
}//

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

#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; }