#include <bits/stdc++.h>
#define fi first
#define se second
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define rrep(i,n) for(int i = 1; i <= (n); ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define rng(a) a.begin(),a.end()
#define maxs(x,y) (x = max(x,y))
#define mins(x,y) (x = min(x,y))
#define limit(x,l,r) max(l,min(x,r))
#define lims(x,l,r) (x = max(l,min(x,r)))
#define isin(x,l,r) ((l) <= (x) && (x) < (r))
#define pb push_back
#define sz(x) (int)(x).size()
#define pcnt __builtin_popcountll
#define uni(x) x.erase(unique(rng(x)),x.end())
#define snuke srand((unsigned)clock()+(unsigned)time(NULL));
#define show(x) cout<<#x<<" = "<<x<<endl;
#define PQ(T) priority_queue<T,v(T),greater<T> >
#define bn(x) ((1<<x)-1)
#define dup(x,y) (((x)+(y)-1)/(y))
#define newline puts("")
#define v(T) vector<T>
#define vv(T) v(v(T))
using namespace std;
typedef long long int ll;
typedef unsigned uint;
typedef unsigned long long ull;
typedef pair<int,int> P;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<P> vp;
inline int in() { int x; scanf("%d",&x); return x;}
template<typename T>inline istream& operator>>(istream&i,v(T)&v)
{rep(j,sz(v))i>>v[j];return i;}
template<typename T>string join(const v(T)&v)
{stringstream s;rep(i,sz(v))s<<' '<<v[i];return s.str().substr(1);}
template<typename T>inline ostream& operator<<(ostream&o,const v(T)&v)
{if(sz(v))o<<join(v);return o;}
template<typename T1,typename T2>inline istream& operator>>(istream&i,pair<T1,T2>&v)
{return i>>v.fi>>v.se;}
template<typename T1,typename T2>inline ostream& operator<<(ostream&o,const pair<T1,T2>&v)
{return o<<v.fi<<","<<v.se;}
template<typename T>inline ll suma(const v(T)& a) { ll res(0); for (auto&& x : a) res += x; return res;}
const double eps = 1e-10;
const ll LINF = 1001002003004005006ll;
const int INF = 1001001001;
#define dame { puts("-1"); return 0;}
#define yn {puts("YES");}else{puts("NO");}
const int MX = 200005;
const int mod = 1000000007;

#define bsf __builtin_ctzll
ll gcd(ll a, ll b) {
  // a = abs(a); b = abs(b);
  if (!a || !b) return a|b;
  int t = bsf(a|b); a >>= bsf(a);
  do { b >>= bsf(b); if (a > b) swap(a, b); b -= a;} while (b);
  return a << t;
}
// ax+by = gcd(a,b)
ll extgcd(ll a, ll b, ll& x, ll& y) {
  for (ll u = y = 1, v = x = 0; a;) {
    ll q = b / a; swap(x -= q * u, u);
    swap(y -= q * v, v); swap(b -= q * a, a);
  }
  return b;
}
//
inline int inv(int a, int p) {
  ll x, y;
  extgcd(a,p,x,y);
  return (x%p+p)%p;
}

int main() {
  int n = 3;
  vi r(n), p(n);
  rep(i,n) scanf("%d%d",&r[i],&p[i]);
  rep(i,n) {
    rep(j,i) {
      int g = gcd(p[i],p[j]);
      if (r[i]%g != r[j]%g) dame;
      p[i] /= g; p[j] /= g;
      int gi = gcd(p[i],g);
      int gj = g/gi;
      while (g = gcd(gi,gj), g != 1) {
        gi *= g;
        gj /= g;
      }
      p[i] *= gi;
      p[j] *= gj;
      r[i] %= p[i];
      r[j] %= p[j];
    }
  }
  vl x;
  rep(i,n) {
    ll a = r[i], c = 1;
    rep(j,i) {
      a -= x[j]*c%p[i];
      if (a < 0) a += p[i];
      c = c*p[j]%p[i];
    }
    rep(j,i) a = a*inv(p[j],p[i])%p[i];
    x.pb(a);
    // cerr<<r[i]<<" "<<p[i]<<" "<<a<<endl;
  }

  ll ans = 0, c = 1;
  rep(i,n) {
    ans += x[i]*c;
    c = c*p[i];
  }
  if (x == vl(n)) {
    ans = 1;
    rep(i,n) ans = ans*p[i];
  }
  cout<<ans<<endl;
  return 0;
}