#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <deque>
#include <cstdio>
#include <set>
#include <map>
#include <bitset>
#include <stack>
#include <cctype>
using namespace std;
int main() {
	int a, b;
	cin >> a >> b;
	if (b == 0) {
		cout << "1" << endl;
		return 0;
	}
	if (a > 0) {
		cout << "-1" << endl;
		return 0;
	}
	if (a == -1) {
		cout << "2" << endl;
		return 0;
	}
	cout << "-1" << endl;
	return 0;
}