//#include <atcoder/all>
#include <bits/stdc++.h>
using namespace std;
using lint = long long;
constexpr lint mod = 1e9 + 7;
#define all(x) begin(x), end(x)
#define bitcount(n) __builtin_popcountll((lint)(n))
#define fcout cout << fixed << setprecision(15)
#define highest(x) (63 - __builtin_clzll(x))
#define rep(i, n) for(int i = 0; i < int(n); i++)
#define rep2(i, l, r) for(int i = int(l); i < int(r); i++)
#define repr(i, n) for(int i = int(n) - 1; i >= 0; i--)
#define repr2(i, l, r) for(int i = int(r) - 1; i >= int(l); i--)
#define accumulate you cannot use this word!
constexpr int inf9 = 1e9; constexpr lint inf18 = 1e18;
inline void Yes(bool condition){ if(condition) cout << "Yes" << endl; else cout << "No" << endl; }
template<class itr> void array_output(itr start, itr goal){ for(auto i = start; i != goal; i++) cout << (i == start ? "" : " ") << (*i); cout << endl; }
template<class itr> void cins(itr first, itr last){ for(auto i = first; i != last; i++){ cin >> (*i); } }
template<class T> T gcd(T a, T b){ if(b) return gcd(b, a % b); else return a; }
template<class T> T lcm(T a, T b){ return a / gcd(a, b) * b; }
template<class T> bool chmax(T &a, const T &b){ if(a < b){ a = b; return 1; } return 0; }
template<class T> bool chmin(T &a, const T &b){ if(b < a){ a = b; return 1; } return 0; }
inline int has(lint i, int j){ return (i >> j) & 1; }
int dy[4] = {1, 0, -1, 0}; int dx[4] = {0, 1, 0, -1};
bool is_inside(lint y, lint x, lint H, lint W){ return (0 <= y && y < H && 0 <= x && x < W); }

struct io_init {
    io_init() {
        cin.tie(nullptr); cout.tie(nullptr);
        std::ios::sync_with_stdio(false);
    }
} io_init;

tuple<lint, lint, lint> extgcd(lint a, lint b){
    if(b == 0){
        return {1, 0, a};
    }
    auto [x, y, g] = extgcd(b, a % b);
    return {y, x - (a / b) * y, g};
}

lint signed_mod(lint x, lint modulo) {
    return (x % modulo + modulo) % modulo;
}

//tuple<lint, lint, bool> IndeterminateEquation(lint a, lint b, lint c){ // return: x, y, is_valid
//    auto [x, y, g] = extgcd(a, b);
//    if(c % g != 0) return {0, 0, false};
//
//    x *= c / g;
//    y *= c / g;
//
//    assert(a * x + b * y == c);
//    return {x, y, true};
//}

pair<lint, lint> CRT(lint a1, lint m1, lint a2, lint m2){ // return: a, m
    a1 = signed_mod(a1, m1);
    a2 = signed_mod(a2, m2);
    
    auto [b, c, g] = extgcd(m1, m2);
    if(a1 % g != a2 % g) return {-1, -1};
    
    lint m = m1 / g * m2;
    lint tmp = ((a2 - a1) / g) * b % (m2 / g);
    lint a = tmp * m1 + a1;
    a = signed_mod(a, m);
    return {a, m};
}

int main(){
    lint x1, y1, x2, y2, x3, y3;
    cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
    auto [x12, y12] = CRT(x1, y1, x2, y2);
    if(x12 == -1){
        cout << -1 << endl;
        return 0;
    }
    
    auto [x123, y123] = CRT(x12, y12, x3, y3);
    if(x123 == -1){
        cout << -1 << endl;
        return 0;
    }
    
    if(x123 == 0) x123 += y123;
    assert(1 <= x123 && x123 <= y123);
    cout << x123 << endl;
}