#include <iostream>
#include <utility>
#include <vector>
#include <string>
#include <cmath>
#include <algorithm>
#include <functional>
#include <iomanip>
#include <map>
#include <set>
#include <queue>
using namespace std;
using ll = long long int;
#define chmax(x,y)  x = (x > (y)) ? x : (x = (y));
#define chmin(x,y)  x = (x < (y)) ? x : (x = (y));

ll mod(ll a, ll m) {
    return (a % m + m) % m;
}

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;
}

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

int main(int argc, char const *argv[])
{
  vector<ll> B,M;
  for(int i=0;i<3;++i)
  {
    ll a,b; cin >> a >> b;
    B.emplace_back(a);
    M.emplace_back(b);
  }
  auto answer = crt(B,M);
  if(answer.first == 0)answer.first = -1;
  std::cout << answer.first << std::endl;
}