#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define MOD int(1e9+7)
#define INF int(1e9+7)
#define LINF ll(1e18+7)
#define PI acos(-1)
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define P pair<ll,ll>
#define chmax(x,y) (x = max(x,y))
#define chmin(x,y) (x = min(x,y))

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

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

// 
int main(){
  vector<ll> b(3),m(3);
  rep(i,3) cin>>b[i]>>m[i];
  ll r,mod;
  tie(r,mod) = crt(b,m);
  if(P(r,mod)==P(0,0)) cout<<-1<<endl;
  else cout<<r<<endl;
}