#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#define ll long long
using namespace std;

template <typename T>
struct CRT {
	vector<T> rem, mod;
	void add(T r, T m) {
		rem.emplace_back(r);
		mod.emplace_back(m);
	}
	pair<T,T> calc() {
		T r = 0, m = 1;
		for (int i=0; i<(int)rem.size(); i++) {
			auto ext_gcd = [](T a, T b, T &x, T &y, T &d) -> void {
				x = 1, y = 0;
				T u = 0, v = 1;
				while (b) {
					T p = a/b, q = a%b, r = x-u*p;
					x = u, u = r;
					r = y-v*p;
					y = v, v = r;
					a = b, b = q;
				}
				d = a;
			};
			T p, q, d;
			ext_gcd(m, mod[i], p, q, d);
			if ((rem[i]-r)%d != 0) return {0, 0};
			T t = (rem[i]-r)/d*p%(mod[i]/d);
			r += m*t;
			m *= mod[i]/d;
		}
		return {r<0?r+m:r, m};
	}
};

void solve() {
	CRT<ll> crt;
	for (int i=0; i<3; i++) {
		ll x, y;
		cin >> x >> y;
		crt.add(x, y);
	}
	auto [r, m] = crt.calc();
	cout << (m?r?r:m:-1) << '\n';
}

signed main() {
	cin.tie(nullptr);
	ios_base::sync_with_stdio(false);
	solve();
	return 0;
}