#include
#include
using namespace std;
int main()
{
int n;
cin >> n;
if(n < 4)
{
cout << "infant\n";
}
else if(n < 13)
{
cout << "child\n";
}
else if(n < 19)
{
cout << "youngster\n";
}
else { cout << "youth\n" } return 0; }