#include <iostream>
#include <string>
#include <math.h>
#include <algorithm>
#include <utility>
using namespace std;

int X, Y, ans;

int main(){
	cin >> X >> Y;
	
	if(X == Y){ ans = 0;}
	else if(Y == 0){ ans = 1;}
	else if(X == 0){ ans = 2;}
	else {ans = -1;}
	
	cout << ans << endl;
}