#include <iostream>
#include <cstring>
#include <queue>
using namespace std;

int main()
{
int x, y;
int ex, ey;
cin >> x >> y;
cin >> ex >> ey;
if( x + y != ex + ey)
{
cout << -1 << endl;
return 0;
}
int zbir = x + y;
bool vis[200001];
memset(vis, 0, sizeof(vis));
queue <int> q, cekori;
q.push(x);
cekori.push(0);

while(!q.empty())
{
int temeX = q.front();
int cek = cekori.front();
q.pop();
cekori.pop();
if( temeX == ex )
{
cout << cek << endl;
break;
}
int temeY = zbir - temeX;
if( temeY - 1 > 0 && vis[temeX + 1] == false)
{
vis[temeX + 1] = true;
q.push(temeX + 1);
cekori.push(cek + 1);
}
if (temeX-1-((2*temeX)%31) > 0 && vis[temeX-1-((2*temeX)%31)]==false)
{
vis[temeX-1-((2*temeX)%31)] = true;
q.push(temeX-1-((2*temeX)%31));
cekori.push(cek + 1);
}
}
return 0;
}