#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MOD=1000000007;
#define INF 1LL<<30
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define all(x) (x).begin(),(x).end()

int main() {
    int a,b;
    cin>>a>>b;
    if(b==0) cout<<1<<endl;
    else if(a==-1) cout<<2<<endl;
    else cout<<-1<<endl;
}