#include <stdio.h>

int main(void) {
	// your code goes here
	int x = 13, y = -5;
	
	printf("before: %d %d\n",x,y);
	
	x = x ^ y;
	y = x ^ y;
	x = x ^ y;
	
	printf(" after: %d %d\n",x,y);
	return 0;
}