A rock paper scissors game with modular arithmetic

rps.c

#include <stdio.h>
#include <stdlib.h>

#define MOD(x, k) ((x) % (k) + ((k))) % (k)

int main() {
	int p1, p2;

	puts(
	"Welcome to Rock, Paper, Scissors\n"
	"0 - Rock\n"
	"1 - Paper\n"
	"2 - Scissors");

	printf("Player 1, Enter your choice.\n>");
	scanf("%d", &p1);
	
	printf("Player 2, Enter your choice.\n>");
	scanf("%d", &p2);

	if (!(p1 - p2)) {
	       printf("The game was a tie.\n");
	       return main();
	}	       

	printf("Player %c won the game\n", (MOD(p1 - p2, 3) + 48));
	return 0; 
}