#include <math.h>

#define min(a, b) ((a) < (b) ? (a) : (b))
#define max(a, b) ((a) > (b) ? (a) : (b))

typedef long long integer;

integer factorial(integer n);
integer permutations_no_repetition(integer n, integer r);
integer permutations_with_repetition(integer n, integer r);
integer combinations_no_repetition(integer n, integer r);
integer combinations_with_repetition(integer n, integer r);