Codeforces Round #388 (Div. 2), problem: (B) Parallelogram is Back Solution in C/C++

Codeforces Round #388 (Div. 2), problem: (B) Parallelogram is Back Solution in C/C++

int main()
{
	int x1,y1,x2,y2,x3,y3;
	
	scanf("%d%d\n%d%d\n%d%d",&x1,&y1,&x2,&y2,&x3,&y3);
	printf("3\n%d %d\n%d %d\n%d %d",x1+x2-x3,y1+y2-y3,x2+x3-x1,y2+y3-y1,x3+x1-x2,y3+y1-y2);
	
	return 0;
}