#include<cstdio>
int main(void) {
	int X, Y;
	scanf("%d%d", &X, &Y);
	if (X == Y)  { printf("0\n"); }	
	else if (X + Y == 0) { printf("3\n"); }
	else if (X == 0) { printf("2\n"); }
	else if (Y == 0) { printf("1\n"); }
	else { printf("-1\n"); }
		return 0;
}