#include <cstdio>
int main()
{
double n = 3; // libolné liché
printf("n * (n - 1) / 2 = %f\n", n * (n - 1) / 2);
printf("n / 2 * (n - 1) = %f\n", n / 2 * (n - 1));
return 0;
}
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