#include<bits/stdc++.h>
using namespace std;
#define ALL(x) begin(x),end(x)
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define mod 1000000007
using ll=long long;
const int INF=1000000000;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0},dy[]={0,1,0,-1};
// ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}

struct IOSetup{
    IOSetup(){
        cin.tie(0);
        ios::sync_with_stdio(0);
        cout<<fixed<<setprecision(12);
    }
} iosetup;
 
template<typename T>
ostream &operator<<(ostream &os,const vector<T>&v){
    for(int i=0;i<(int)v.size();i++) os<<v[i]<<(i+1==(int)v.size()?"":" ");
    return os;
}
template<typename T>
istream &operator>>(istream &is,vector<T>&v){
    for(T &x:v)is>>x;
    return is;
}

// (val, mod)
pair<ll,ll> Garner(const vector<ll> &rems,const vector<ll> &mods){
    // {g, x}, g=gcd(a,b), xa = g (mod b)
    function<pair<ll,ll>(ll,ll)> gcd_inv=[](ll a,ll b){
        a%=b;
        if(a<0) a+=b;
        if(a==0) return make_pair(b,0ll);
        ll s=b,t=a,m0=0,m1=1;
        while(t){
            ll u=s/t;
            s-=t*u,m0-=m1*u;
            swap(s,t);
            swap(m0,m1);
        }
        if(m0<0) m0+=b/s;
        return make_pair(s,m0);
    };

    ll R=0,M=1;
    for(int i=0;i<(int)rems.size();i++){
        ll r=rems[i],m=mods[i];
        r%=m;if(r<0) r+=m;
        if(m>M) swap(m,M),swap(r,R);
        if(M%m==0){
            if(R%m!=r) return {0,0};
            continue;
        }
        auto [g,iM]=gcd_inv(M,m);
        ll u=m/g;
        if((r-R)%g) return {0,0};
        ll x=(r-R)/g%u*iM%u;
        R+=x*M;
        M*=u;
        if(R<0) R+=M;
    }
    return {R,M};
}

signed main(){

    vector<ll> r(3),m(3);
    rep(i,3) cin>>r[i]>>m[i];

    auto p=Garner(r,m);
    if(p.second==0) cout<<-1<<endl;
    else cout<<p.first<<endl;
    return 0;
}