#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define REP(i, n)           for(int(i)=0;(i)<(n);++(i))
#define FOR(i, f, t)        for(int(i)=(f);(i)<(t);(++i))

ll gcd(ll n, ll m){return m?gcd(m,n%m):n;}
ll lcm(ll n, ll m){return n/gcd(n,m)*m;}

int main(){
    ll x1,y1,x2,y2,x3,y3;
    cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;

    // a = x1 + y1 * b1
    //   = x2 + y2 * b2
    //   = x3 + y3 * b3

    ll a = x1;
    REP(i,y2+1){
        if(a % y2 == x2) break;
        a += y1;
    }

    ll y = lcm(y1,y2);
    REP(i,y3+1){
        if(a % y3 == x3) break;
        a += y;
    }
    if(a % y1 != x1 || a % y2 != x2 || a % y3 != x3){
        cout << -1 << endl;
        return 0;
    }
    if(a == 0) a = lcm(y,y3);
    cout << a << endl;
}