# include "bits/stdc++.h"
using namespace std;
using LL = long long;
using ULL = unsigned long long;
const double PI = acos(-1);
template<class T>constexpr T INF() { return ::std::numeric_limits<T>::max(); }
template<class T>constexpr T HINF() { return INF<T>() / 2; }
template <typename T_char>T_char TL(T_char cX) { return tolower(cX); };
template <typename T_char>T_char TU(T_char cX) { return toupper(cX); };
typedef pair<LL, LL> pii;
const int vy[] = { -1, -1, -1, 0, 1, 1, 1, 0 }, vx[] = { -1, 0, 1, 1, 1, 0, -1, -1 };
const int dx[4] = { 0,1,0,-1 }, dy[4] = { 1,0,-1,0 };
int popcnt(unsigned long long n) { int cnt = 0; for (int i = 0; i < 64; i++)if ((n >> i) & 1)cnt++; return cnt; }
int d_sum(LL n) { int ret = 0; while (n > 0) { ret += n % 10; n /= 10; }return ret; }
int d_cnt(LL n) { int ret = 0; while (n > 0) { ret++; n /= 10; }return ret; }
LL gcd(LL a, LL b) { if (b == 0)return a; return gcd(b, a%b); };
LL lcm(LL a, LL b) { LL g = gcd(a, b); return a / g*b; };
# define ALL(qpqpq)           (qpqpq).begin(),(qpqpq).end()
# define UNIQUE(wpwpw)        sort(ALL((wpwpw)));(wpwpw).erase(unique(ALL((wpwpw))),(wpwpw).end())
# define LOWER(epepe)         transform(ALL((epepe)),(epepe).begin(),TL<char>)
# define UPPER(rprpr)         transform(ALL((rprpr)),(rprpr).begin(),TU<char>)
# define FOR(i,tptpt,ypypy)   for(LL i=(tptpt);i<(ypypy);i++)
# define REP(i,upupu)         FOR(i,0,upupu)
# define INIT                 std::ios::sync_with_stdio(false);std::cin.tie(0)

// a x + b y = gcd(a, b)
LL extgcd(LL a, LL b, LL &x, LL &y) {
    LL g = a; x = 1; y = 0;
    if (b != 0) g = extgcd(b, a % b, y, x), y -= (a / b) * x;
    return g;
}

//a x ≡ m (mod m)
LL mod_inverse(LL a, LL m){
    LL x, y;
    extgcd(a, m, x, y);
    return (m + x%m)%m;
}

//(b, m)
pair<LL, LL>linear_congruence(const vector<LL>& A, const vector<LL>& B, const vector<LL>& M){
    //最初は条件がないのですべての整数を意味するx≡0(mod 1)を解としておく
    LL x = 0, m = 1;
    for(int i = 0;i < (int)A.size();i++){
        LL a = A[i]*m, b = B[i] - A[i]*x, d = gcd(M[i], a);
        if(b % d != 0)return make_pair(-1, 0); //解がない
        LL t = b/d*mod_inverse(a/d, M[i]/d)%(M[i]/d);
        x = x + m*t;
        m *= M[i]/d;
    }
    return make_pair(x%m, m);
}

vector<LL> x(3), y(3), A(3, 1);

int main(){
    INIT;
    REP(i, 3)cin >> x[i] >> y[i];
    pair<LL, LL> p = linear_congruence(A, x, y);
    cout << p.first << endl;
}