#include <bits/stdc++.h>
#define rep(i, a, n) for(int i = a; i < (n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;
const int INF = 1001001001;
const ll LINF = 1001002003004005006ll;
//const int mod = 1000000007;
//const int mod = 998244353;

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

//
// let (r, m) be return value, the solution is x ≡ r (mod. m)
pair<long long, long long> CRT(const vector<long long>& b, const vector<long long>& m) {
  long long r = 0, M = 1;
  for (int i = 0; i < (int)b.size(); i++) {
    long long p, q;
    long long d = extGCD(M, m[i], p, q); // p is inv of M/d (mod. m[i]/d)
    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((r%M+M)%M, M);
}

int main()
{
  int n = 3;
  vector<ll> b(n), m(n);
  bool flag = false;
  rep(i, 0, n) {
    cin >> b[i] >> m[i];
    if (b[i]) flag = true;
  }
  
  auto res = CRT(b, m);
  if (res.second == -1) cout << -1 << endl;
  else if (flag) cout << res.first << endl;
  else cout << res.second << endl;
  return 0;
}