#include <bits/stdc++.h>
#define ll long long
#define INF 1000000005
#define MOD 1000000007
#define EPS 1e-10
#define rep(i,n) for(int i=0;i<(int)(n);++i)
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;--i)
#define srep(i,s,t) for(int i=(int)(s);i<(int)(t);++i)
#define each(a,b) for(auto& (a): (b))
#define all(v) (v).begin(),(v).end()
#define len(v) (int)(v).size()
#define zip(v) sort(all(v)),v.erase(unique(all(v)),v.end())
#define cmx(x,y) x=max(x,y)
#define cmn(x,y) x=min(x,y)
#define fi first
#define se second
#define pb push_back
#define show(x) cout<<#x<<" = "<<(x)<<endl
#define spair(p) cout<<#p<<": "<<p.fi<<" "<<p.se<<endl
#define sar(a,n) cout<<#a<<":";rep(pachico,n)cout<<" "<<a[pachico];cout<<endl
#define svec(v) cout<<#v<<":";rep(pachico,v.size())cout<<" "<<v[pachico];cout<<endl
#define svecp(v) cout<<#v<<":";each(pachico,v)cout<<" {"<<pachico.first<<":"<<pachico.second<<"}";cout<<endl
#define sset(s) cout<<#s<<":";each(pachico,s)cout<<" "<<pachico;cout<<endl
#define smap(m) cout<<#m<<":";each(pachico,m)cout<<" {"<<pachico.first<<":"<<pachico.second<<"}";cout<<endl

using namespace std;

typedef pair<int,int> P;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<double> vd;
typedef vector<P> vp;
typedef vector<string> vs;

const int MAX_N = 100005;

ll gcd(ll a,ll b)
{
    if(a == 0 || b == 0){
        return max(a,b);
    }
    if(a % b == 0){
        return b;
    }else{
        return gcd(b,a%b);
    }
}

template <typename T>
void extgcd(T a, T b, T& x, T& y)
{
	if(b != 0){
		extgcd(b,a%b,y,x);
		y -= (a/b)*x;
	}else{
		x = 1;
		y = 0;
	}
}

template <typename T>
pair<T, T> CRT(const pair<T, T>& a1, const pair<T, T>& a2)
{
    const T v1 = a1.first, m1 = a1.second;
    const T v2 = a2.first, m2 = a2.second;
    T g = gcd(m1, m2);
    T dev = (v2 - v1) / g;
    T mod = abs(v2 - v1) % g;
    if(mod) return make_pair(-1,-1);
    T x, y;
    extgcd(m1 / g, m2 / g, x, y);
    x *= dev, y *= dev;
    const T m = m1 / g * m2;
    return make_pair(((((__int128)m1 * x + v1) % m) + m) % m, m);
}

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    pll p[3];
    rep(i,3){
        cin >> p[i].fi >> p[i].se;
    }
    auto r1 = CRT<ll>(p[0],p[1]);
    if(r1.fi == -1){
        cout << "-1\n";
        return 0;
    }
    auto r2 = CRT<ll>(r1,p[2]);
    if(r2.fi == 0){
        cout << r2.se << "\n";
    }else{
        cout << r2.fi << "\n";
    }
    return 0;
}