#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i,N) for(int i=0;i<int(N);++i)
#define rep1(i,N) for(int i=1;i<int(N);++i)
#define all(a) (a).begin(),(a).end()
#define bit(k) (1LL<<(k))
#define SUM(v) accumulate(all(v), 0LL)

typedef pair<int, int> i_i;
typedef pair<ll, ll> l_l;
template <class T> using vec = vector<T>;
template <class T> using vvec = vector<vec<T>>;
struct fast_ios{ fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; }fast_ios_;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }

#define TOSTRING(x) string(#x)
template <typename T> istream &operator>>(istream &is, vector<T> &vec) { for (T &x : vec) is >> x; return is; }
template <typename T> ostream &operator<<(ostream &os, const vector<T> &v) { os  << "["; for(auto _: v) os << _ << ", "; os << "]"; return os; };
template <typename T> ostream &operator<<(ostream &os, set<T> &st) { os << "("; for(auto _: st) { os << _ << ", "; } os << ")";return os;}
template <typename T> ostream &operator<<(ostream &os, multiset<T> &st) { os << "("; for(auto _: st) { os << _ << ", "; } os << ")";return os;}
template <typename T, typename U> ostream &operator<<(ostream &os, const pair< T, U >& p){os << "{" <<p.first << ", " << p.second << "}";return os; }
template <typename T, typename U> ostream &operator<<(ostream &os, const map<T, U> &mp){ os << "["; for(auto _: mp){ os << _ << ", "; } os << "]" << endl; return os; }

#define DUMPOUT cerr
void dump_func(){ DUMPOUT << endl; }
template <class Head, class... Tail> void dump_func(Head &&head, Tail &&... tail) { DUMPOUT << head; if (sizeof...(Tail) > 0) { DUMPOUT << ", "; } dump_func(std::move(tail)...); }

#ifdef DEBUG
#define dbg(...) { dump_func(__VA_ARGS__) }
#define dump(...) DUMPOUT << string(#__VA_ARGS__) << ": "; dump_func(__VA_ARGS__)
#else
#define dbg(...)
#define dump(...)
#endif

const int INF = (ll)1e9;
const ll INFLL = (ll)1e18+1;
const ll MOD = 1000000007;
// const ll MOD = 998244353;
const long double PI = acos(-1.0);

/*
const int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
const int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
const string dir = "DRUL";
*/



long long extGCD(long long a, long long b, long long &x, long long &y) {
    if (b == 0) {
        x = 1;
        y = 0;
        return a;
    }
    long long x2, y2;
    long long d = extGCD(b, a%b, x2, y2);
    x = y2;
    y = x2 - (a / b) * y2;
    return d;
}


long long mod_inv(long long a, long long m){
    long long x, y;
    long long d = extGCD(a, m, x, y);
    if(d != 1){
        return -1;
    }
    x %= m;
    if(x < 0)x += m;
    return x;
}

std::pair<long long, long long> crt(const std::vector<long long> &r, 
                                    const std::vector<long long> &m){
    assert(r.size() == m.size());
    long long R = 0, M = 1; // Rに
    int n = r.size();
    for(int i = 0; i < n; i++){
        long long p, q;
        long long d = extGCD(M, m[i], p, q); // pはM/dのm[i]/dを法としたときの逆元
        if((r[i] - R) % d != 0){
            return {0, -1};
        }
        long long s = (r[i]-R)/d;
        long long tmp = s * p % (m[i]/d);
        R += M * tmp;
        M *= m[i]/d;
    }
    return make_pair((R%M+M)%M, M);
}
int main() {
    vector<ll> X(3), Y(3);
    rep(i,3){
        cin >> X[i] >> Y[i];
    }
    auto [ans, lcm] = crt(X, Y);
    if(lcm == -1){
        cout << -1 << endl;
    }
    else{
        cout << ans << endl;
    }
}