#include<stdio.h>
main() {
	int x, y, f, max;
	for(x=-10;x<=10;x++) {
		for(y=-10;y<=10;y++) {
			f = x*x - 9*x*y + y*y;
			if ((x==-10)&&(y==-10))
				max = f;
			else if (f>max)
				max = f;
		}
	}
	printf("El max es %d\n", max);
}