#include <bits/stdc++.h>
using namespace std;
#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define REPR(i,n) for (int i=(int)(n)-1;i>=0;--i)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();++i)
#define ALL(c) (c).begin(), (c).end()
#define valid(y,x,h,w) (0<=y&&y<h&&0<=x&&x<w)
#define tpl(...) make_tuple(__VA_ARGS__)
const int INF = 0x3f3f3f3f;
const double EPS = 1e-8;
const double PI = acos(-1);
const int dy[] = {-1,0,1,0};
const int dx[] = {0,1,0,-1};
typedef long long ll;
typedef pair<int,int> pii;
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; }
template<typename Ch,typename Tr,typename C,typename=decltype(begin(C()))>basic_ostream<Ch,Tr>& operator<<(basic_ostream<Ch,Tr>&os,
const C& c){os<<'[';for(auto i=begin(c);i!=end(c);++i)os<<(i==begin(c)?"":" ")<<*i;return os<<']';}
template<class S,class T>ostream&operator<<(ostream &o,const pair<S,T>&t){return o<<'('<<t.first<<','<<t.second<<')';}
template<int N,class Tp>void output(ostream&,const Tp&){}
template<int N,class Tp,class,class ...Ts>void output(ostream &o,const Tp&t){if(N)o<<',';o<<get<N>(t);output<N+1,Tp,Ts...>(o,t);}
template<class ...Ts>ostream&operator<<(ostream&o,const tuple<Ts...>&t){o<<'(';output<0,tuple<Ts...>,Ts...>(o,t);return o<<')';}
template<class T>void output(T t,char z=10){if(t<0)t=-t,putchar(45);int c[20];
int k=0;while(t)c[k++]=t%10,t/=10;for(k||(c[k++]=0);k;)putchar(c[--k]^48);putchar(z);}
template<class T>void outputs(T t){output(t);}
template<class S,class ...T>void outputs(S a,T...t){output(a,32);outputs(t...);}
template<class T>void output(T *a,int n){REP(i,n)cout<<a[i]<<(i!=n-1?',':'\n');}
template<class T>void output(T *a,int n,int m){REP(i,n)output(a[i],m);}
template<class T>bool input(T &t){int n=1,c;for(t=0;!isdigit(c=getchar())&&~c&&c-45;);
if(!~c)return 0;for(c-45&&(n=0,t=c^48);isdigit(c=getchar());)t=10*t+c-48;t=n?-t:t;return 1;}
template<class S,class ...T>bool input(S&a,T&...t){input(a);return input(t...);}
template<class T>bool inputs(T *a, int n) { REP(i,n) if(!input(a[i])) return 0; return 1;}

ll mulmod(ll a, ll n, ll m) {
  ll res = 0;
  while(n>=1) {
    if (n & 1) res = (res + a) % m;
    a = a * 2 % m;
    n >>= 1;
  }
  return res;
}

ll extgcd(ll a, ll b, ll &x, ll &y) {
  ll g = a;
  x = 1; y = 0;
  if (b) {
    g = extgcd(b, a%b, y, x);
    y -= (a/b) * x;
  }
  return g;
}
ll invMod(ll a, ll p) {
  ll x, y;
  if (extgcd(a,p,x,y) == 1) return (x+p)%p;
  return 0;
}

pair<ll,ll> ChineseRemainderTheorem2(const vector<ll> &B, const vector<ll> &M) {
  int n = B.size();
  ll x=0,m=1,a,b,d;
  REP(i,n) {
    a = m, b = B[i] - x, d = __gcd(M[i], a);
    if (b % d) return make_pair(0,-1);
    ll k = M[i]/d;
    ll t = (mulmod(b/d,invMod(a/d, k),k)+k)%k;
    x += m*t;
    m *= k;
  }
  return make_pair(x % m, m);
}

ll lcm(const vector<ll> &v) {
  ll res = 1;
  for (auto a : v)
    res = res/__gcd(res,a) * a;
  return res;
}

int main() {
  while(1) {
    vector<ll> x(3),y(3);
    bool eof = 0;
    REP(i,3) {
      if (!(cin>>x[i]>>y[i])) eof = 1;
    }
    if (eof) break;
    auto p = ChineseRemainderTheorem2(x,y);
    ll res = p.first;
    if (res == 0) res = p.second;
    cout << res << endl;
  }
}