#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;

using mint = modint1000000007;
using mint1 = modint998244353;
typedef long long ll;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef pair<int, int> P;
typedef pair<ll, ll> PL;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<vvd> vvvd;
typedef vector<mint> vm;
typedef vector<vm> vvm;
typedef vector<vvm> vvvm;
typedef vector<mint1> vm1;
typedef vector<vm1> vvm1;
typedef vector<vvm1> vvvm1;
typedef vector<modint> vm2;
typedef vector<vm2> vvm2;
typedef vector<vvm2> vvvm2;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<vvb> vvvb;
typedef vector<char> vc;
typedef vector<vc> vvc;
typedef vector<vvc> vvvc;
typedef vector<PL> vp;
typedef tuple<ll, ll, ll> tt;
typedef vector<tuple<ll, ll, ll>> vt;
typedef vector<string> vs;

struct Edge{
  long long to;
  long long cost;
};
typedef vector<vector<Edge> > Graph;

const long long INF = 1e9;
const long long INFL = 1e18;
const double PI = 3.14159265358979;
const double epsilon = 1e-12;

vector<int> dy = {1, 0, -1, 0};
vector<int> dx = {0, 1, 0, -1};




int main(){
  vl x(3), y(3);
  for(int i=0;i<3;i++){
    cin >> x[i] >> y[i];
  }
  auto c = crt(x, y);
  if(c.first == 0 && c.second == 0)cout << -1 << endl;
  else if(c.first == 0)cout << c.second << endl;
  else cout << c.first << endl;
  return 0;
}