#define  _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <algorithm>
#include <utility>
#include <functional>
#include <cstring>
#include <queue>
#include <stack>
#include <math.h>
#include <iterator>
#include <vector>
#include <string>
#include <set>
#include <math.h>
#include <iostream> 
#include<map>
#include <iomanip>
#include <time.h>
#include <random>
#include <stdlib.h>
#include <list>
#include <typeinfo>
#include <list>
#include <set>
using namespace std;
#define LONG_INF 10000000000000000
#define MAX_MOD 1000000007
#define REP(i,n) for(long long i = 0;i < n;++i)
int main() {
	long long x[3], y[3];
	REP(i, 3) {
		cin >> x[i] >> y[i];
	}
	for (int i = 0;i <= 100000000;++i) {
		long long hoge = x[0] + y[0] * i;
		if (hoge % y[1] == x[1] && hoge % y[2] == x[2]) {
			cout << hoge << endl;
			return 0;
		}
	}
	cout << -1 << endl;
	return 0;
}