#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i = 0; i < n; i++)
#define rep2(i, x, n) for(int i = x; i <= n; i++)
#define rep3(i, x, n) for(int i = x; i >= n; i--)
#define elif else if
#define sp(x) fixed << setprecision(x)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
using ll = long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
const ll MOD = 1000000007;
//const ll MOD = 998244353;
const int inf = (1<<30)-1;
const ll INF = (1LL<<60)-1;
const double pi = acos(-1.0);
const double EPS = 1e-10;
template<typename T> bool chmax(T &x, const T &y) {return (x < y)? (x = y, true) : false;};
template<typename T> bool chmin(T &x, const T &y) {return (x > y)? (x = y, true) : false;};

template<typename T>
T gcd(T a, T b){
    if(b == 0) return a;
    else return gcd(b, a%b);
}

template<typename T>
T lcm(T a, T b){
    return a*b/gcd(a,b);
}

template<typename T>
T extgcd(T a, T b, T &x, T &y){
    if(b == 0) {x = 1, y = 0; return a;}
    T g = extgcd(b, a%b, y, x);
    y -= (a/b)*x;
    return g;
}

template<typename T>
pair<T, T> chinese_remainder_theorem(T a1, T m1, T a2, T m2){
    T x, y, g = extgcd(m1, m2, x, y);
    if((a2-a1)%g != 0) return make_pair(0, -1);
    T m = m1*(m2/g);
    T tmp = (x*((a2-a1)/g)) % (m2/g);
    tmp += m2/g, tmp %= m2/g;
    T a = (m1*tmp+a1) % m;
    return make_pair(a, m);
}

int main(){
    ll a[3], m[3];
    rep(i, 3) cin >> a[i] >> m[i];
    ll A = 0, M = 1;
    rep(i, 3){
        pll p = chinese_remainder_theorem(A, M, a[i], m[i]);
        if(p.second == -1) {cout << -1 << endl; return 0;}
        tie(A, M) = p;
    }
    cout << (A == 0? M : A) << endl;
}