#include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < n; i++)
#define REP(i, n) rep(i, 0, n)
#define repb(i, a, b) for(int i = a; i >= b; i--)
#define all(a) a.begin(), a.end()
#define int long long
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)
using namespace std;
typedef pair<int, int> P;
typedef pair<int, P> PP;
const int mod = 1000000007;
const int INF = 1e12;

int d[1010][1010];

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int x, y;
    cin >> x >> y;
    x += 500; y += 500;
    rep(i, 0, 1010) rep(j, 0, 1010) d[i][j] = INF;
    d[x][y] = 0;    
    priority_queue<PP, vector<PP>, greater<PP> > q;
    q.push(PP(0, P(x, y)));
    while(!q.empty()){
        PP p = q.top(); q.pop();
        int nowd = p.first;
        int nowx = p.second.first;
        int nowy = p.second.second;
        int nextx = nowy + nowx - 500;
        int nexty = nowx - nowy + 500;
        // cout << nowd << " " << nowx << " " << nowy << " " << nextx << " " << nexty << endl;
        if(d[nowy][nowx] > nowd + 1){
            d[nowy][nowx] = nowd + 1;
            q.push(PP(nowd + 1, P(nowy, nowx)));            
        }
        if(nexty < 0 || nexty > 1000 || nextx < 0 || nextx > 1000) continue;
        if(d[nextx][nexty] > nowd + 1){
            d[nextx][nexty] = nowd + 1;
            q.push(PP(nowd + 1, P(nextx, nexty)));
        }
       
        if(nexty == nextx) break;
    }
    int ans = INF;
    rep(i, 0, 1010) chmin(ans, d[i][i]);
    if(ans == INF) ans = -1;
    cout << ans << endl;
}