#include <stdio.h>
 
#define __NARG(unused, _1, _2, _3, _4, _5, VAL, ...) VAL
#define NARG(...) __NARG(unused, ##__VA_ARGS__, 5, 4, 3, 2, 1, 0)
 
#define __STRINGIFY(...) #__VA_ARGS__
#define _STRINGIFY(...) __STRINGIFY(__VA_ARGS__)
#define STRINGIFY(...) _STRINGIFY(__VA_ARGS__)
 
#define DO_SOMETHING_0(...) ZERO
#define DO_SOMETHING_1(...) ONE
#define DO_SOMETHING_2(...) TWO
#define DO_SOMETHING_3(...) THREE
#define DO_SOMETHING_4(...) FOUR
 
#define __DO_SOMETHING(narg, ...) STRINGIFY(DO_SOMETHING_ ## narg (__VA_ARGS__))
#define _DO_SOMETHING(narg, ...) __DO_SOMETHING(narg, __VA_ARGS__)
#define DO_SOMETHING(...) _DO_SOMETHING(NARG(__VA_ARGS__), __VA_ARGS__)
 
int main()
{
    puts(DO_SOMETHING());
    puts(DO_SOMETHING(Hello));
    puts(DO_SOMETHING(Hello, World));
    puts(DO_SOMETHING(Hello, World, This));
    puts(DO_SOMETHING(Hello, World, This, Is));
}

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