#include <library.h>

void list_divisors(const int N, const int first, const int last)
{ if (N % first == 0)
    cout << " " << first;
  if (first < last)
    list_divisors(N, first + 1, last); }

void make_listing(const int first, const int last)
{ cout << first << ":";
  list_divisors(first, 2, first - 1);
  cout << "\n";
  if (first < last)
    make_listing(first + 1, last); }

int main()
{ make_listing(2, 24); }