#include<bits/stdc++.h>
#define int ll
#define rep(i, N) for(int i = 0; i < (int)(N); ++i)
#define rep1(i, N) for(int i = 1; i <= (int)(N); ++i)
#define per(i, N) for(int i = (N)-1; i >= 0; --i)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define bit(n, k) ((n) >> (k))
#define pcnt(n) (__builtin_popcount(n))
#define TakAo(ans) ans ? cout << "Takahashi\n" : cout << "Aoki\n"
#define YesNo(ans) ans ? cout << "Yes\n" : cout << "No\n"
#define endl '\n'
#define fi first
#define se second
#define mkpr make_pair
#define mktpl make_tuple
#define eb emplace_back

using namespace std;
using ll = int64_t;
using ull = uint64_t;
using ld = long double;
using point = struct{ ll x, y; };
using pointld = struct{ ld x, y; };
template<class T> using max_heap = priority_queue<T>;
template<class T> using min_heap = priority_queue<T, vector<T>, greater<T>>;
template<class T> using vec = vector<T>;
template<class T> using vvec = vec<vec<T>>;
template<class T> using vvvec = vec<vvec<T>>;
template<class T> using vvvvec = vvec<vvec<T>>;

constexpr ld EPS = 1e-10;
constexpr int INF = 1001001001;
constexpr ll LINF = 1001001001001001001ll;
constexpr ll MOD = (1) ? 998244353 : 1e9+7;
constexpr int NIL = -1;
constexpr int pm[2] = {1, -1};
constexpr int dy[8] = {0, 1, 1, 1, 0, -1, -1, -1};
constexpr int dx[8] = {1, 1, 0, -1, -1, -1, 0, 1};

ll cel(ll a, ll b){ return (a + b - 1) / b;}
ll Gcd(ll a, ll b){ return b ? Gcd(b, a % b) : abs(a);}
template<class T> T powi(T x, ll exp){
    return exp > 0 ? (exp & 1 ? x : 1) * powi(x * x, exp >> 1) : x / x;
}
ll modpow(ll x, ll exp, ll mod){
    x %= mod;
    return exp > 0 ? (exp & 1 ? x : 1) * modpow(x * x, exp >> 1, mod) % mod : 1;
}
template<class T> bool chmin(T &a, T b){ return a > b ? (a = b, true) : 0;}
template<class T> bool chmax(T &a, T b){ return a < b ? (a = b, true) : 0;}

using Pair = pair<ll, ll>;
using Tpl = tuple<char, int, int>;

ll ExtGcd(ll a, ll b, ll &x, ll &y){
    ll d = a;
    if(b != 0){
        d = ExtGcd(b, a % b, y, x);
        y -= (a / b) * x;
    }
    else{
        x = 1, y = 0;
    }
    return d;
}

pair<ll, ll> ChineseRem(vec<ll> &b, vec<ll> &m) {
    ll r = 0, M = 1;
    for (int i = 0; i < (int)b.size(); ++i) {
        ll p, q;
        ll d = ExtGcd(M, m[i], p, q); // p is inv of M/d (mod. m[i]/d)
        if ((b[i] - r) % d != 0) return make_pair(0, -1);
        ll tmp = (b[i] - r) / d * p % (m[i]/d);
        r += M * tmp;
        M *= m[i]/d;
    }
    return mkpr((r % M + M) % M, M);
}

void Main(){
    vec<ll> B(3), M(3);
    rep(i, 3) cin >> B[i] >> M[i];

    auto ans = ChineseRem(B, M);
    if(ans.se == -1) cout << -1 << endl;
    else if(ans.fi != 0) cout << ans.fi << endl;
    else cout << ans.se << endl;
}
 
signed main(){
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    Main();
    return 0;
}