#include "library.h"

int sum_up_to_1(int max)
{ if (max == 0)
    return 0;
  return sum_up_to_1(max-1) + max; }

int sum_up_to_2(int N)
{ return (N+1)*N/2; }

void perform_tests()
{ print("Enter N: ");
  const int N = read_int();
  int s1 = sum_up_to_1(N);
  int s2 = sum_up_to_2(N);
  print("sum from 1 to ");
  print(N);
  print(" is ");
  print(s1);
  print(" or ");
  print(s2);
  new_line();
  perform_tests(); }

void main()
{ perform_tests(); }