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

#define rep(i,j,n) for(int i=j;i<n;++i)
#define all(i) i.begin(),i.end()
#define rall(i) i.rbegin(), i.rend()
#define INF 1e9
#define LINF 1e18
const int mod = 1e9 + 7;

typedef long long i64;
typedef pair<int, int> pi;

template <class T> using vt = vector<T>;
template <class T> using vvt = vector<vector<T>>;

i64 gcd(i64 n, i64 m) {return (m == 0? n : gcd(m, n % m));}
i64 lcd(i64 n, i64 m) {return (n / gcd(n, m) * m);}
int dx[] = {1, 0, -1, 0};
int dy[] = {0, 1, 0, -1};

long long extgcd(long long a, long long b, long long &x, long long &y) {
  if(b == 0) {
    x = 1; y = 0;
    return a;
  }
  long long d = extgcd(b, a % b, y, x);
  y -= a / b * x;
  return d;
}

inline long long MOD(long long a, long long m) {
  return (a % m + m) % m;
}

pair<long long, long long> ChineseRem(const vector<long long> &b, const vector<long long> &m) {
  long long r = 0, M = 1;
  for(int i = 0; i < b.size(); ++i) {
    long long p, q;
    long long d = extgcd(M, m[i], p, q);
    if((b[i] - r) % d != 0) return make_pair(0, -1);
    long long tmp = (b[i] - r) / d * p % (m[i] / d);
    r += M * tmp;
    M *= m[i] / d;
  }
  return make_pair(MOD(r, M), M);
}

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

  vt<long long> x(3), y(3);
  rep(i, 0, 3) cin >> x[i] >> y[i];

  auto res = ChineseRem(x, y);
  if(res.second == -1) cout << -1 << endl;
  else if(count(all(x), 0) == 3) cout << res.second << endl;
  else cout << res.first << endl;
}