#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
#define rep(i,a) for(int i=0;i<(a);i++)
#define MOD 1000000007

int main(){
  int X,Y; cin>>X>>Y;
  int ans=0;
  if(X<Y){
    swap(X,Y);
    ans++;
  }
  while(X>Y){
    int tmp=X+Y;
    Y=X-Y;
    X=tmp;
    ans++;
  }
  if(X==Y) cout<<ans<<endl;
  else cout<<-1<<endl;
  return 0;
}