#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)
#define FOR(i,b,e) for (int i=(int)(b); i<(int)(e); i++)
#define ALL(x) (x).begin(), (x).end()

const int INF = 1e8;
const double PI = acos(-1);

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  int x, y;
  cin >> x >> y;
  map<pair<int, int>, int> dist;
  queue<pair<int, int> > Q;

  Q.push({x, y});
  dist[{x, y}] = 0;

  int ret = INF;
  while (!Q.empty()) {
    int x1, y1;
    tie(x1, y1) = Q.front();
    Q.pop();
    int d = dist[{x1, y1}];

    if (x1 == y1)
      ret = min(ret, d);
    
    if (!dist.count({y1, x1})) {
      Q.emplace(y1, x1);
      dist[{y1, x1}] = d + 1;
    }

    int x2 = x1 + y1;
    int y2 = x1 - y1;

    if (abs(x2) < 256 && abs(y2) < 256) {
      if (!dist.count({x2, y2})) {
        Q.emplace(x2, y2);
        dist[{x2, y2}] = d + 1;
      }
    }
  }
  
  cout << (ret == INF ? -1 : ret) << endl;
  
  return 0;
}