#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000001


int main(){	
	
	vector<long long> r(3),m(3);
	rep(i,3)cin>>r[i]>>m[i];
	
	auto ans = crt(r,m);
	long long p;
	if(ans.second==0)p = -1;
	else {
		p = ans.first;
		if(p==0)p = ans.second;
	}
	cout<<p<<endl;
	
	return 0;
	
}