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

long long extgcd(long long a, long long b, long long &x, long long &y) {
    for (long long u = y = 1, v = x = 0; a; ) {
        long long q = b / a;
        swap(x -= q * u, u);
        swap(y -= q * v, v);
        swap(b -= q * a, a);
    }
    return b;
}

pair<long long, long long> chinese_rem(vector<long long> b, vector<long long> m) {
    long long r = 0, M = 1;
    for (int i = 0; i < (int)b.size(); ++i) {
        long long p, q, d = extgcd(M, m[i], p, q);
        if ((b[i] - r) % d != 0) return {0, -1};
        r += (b[i] - r) / d * p % (m[i] / d) * M;
        M *= m[i] / d;
    }
    return {(r % M + M) % M, M};
}

int main() {
    vector<long long> b(3), m(3);
    bool exist_non_zero = false;
    for (int i = 0; i < 3; ++i) {
        cin >> b[i] >> m[i];
        if (b[i]) exist_non_zero = true;
    }
    pair<long long, long long> res = chinese_rem(b, m);
    if (res.second == -1) cout << -1 << endl;
    else if (exist_non_zero) cout << res.first << endl;
    else cout << res.second << endl;
}