#include <iostream>
#include <vector>
using namespace std;

inline long long mod(long long a, long long m) {
    return (a % m + m) % m;
}

long long inv(long long a, long long m) {
    long long b = m, u = 1, v = 0;
    while (b) {
        long long t = a/b;
        a -= t*b; swap(a, b);
        u -= t*v; swap(u, v);
    }
    return mod(u, m);
}

long long gcd(long long a, long long b) {
    if (b == 0) return a;
    else return gcd(b, a % b);
}

pair<long long, long long> ChineseRem(vector<long long> vb, vector<long long> vm) {
    long long x = 0, m = 1, a, b, d;
    for (int i = 0; i < vb.size(); ++i) {
        a = m, b = vb[i] - x, d = gcd(vm[i], a);
        if (b % d != 0) return make_pair(0, -1);
        long long t = mod(b/d * inv(a/d, vm[i]/d), vm[i]/d);
        x += m * t;
        m *= vm[i]/d;
    }
    return make_pair(x % m, m);
}

int main() {
    vector<long long> vb(3), vm(3);
    for (int i = 0; i < 3; ++i) {
        cin >> vb[i] >> vm[i];
    }
    
    pair<long long, long long> res = ChineseRem(vb, vm);
    if (res.second == -1) cout << -1 << endl;
    else {
        if (res.first == 0) cout << res.second << endl;
        else cout << res.first << endl;
    }
}