#include <bits/stdc++.h>   using namespace std;   using ll = long long;   template <class t, class u>   void chmax(t& first, u second) {     if (first < second) first = second;   }   template <class t, class u>   void chmin(t& first, u second) {     if (second < first) first = second;   }   template <class t>   using vc = vector<t>;   template <class t>   using vvc = vc<vc<t>>;   using pi = pair<ll, ll>;   using vi = vc<ll>;   template <class t, class u>   ostream& operator<<(ostream& os, const pair<t, u>& p) {     return os <<  {  << p.first <<  ,  << p.second <<  } ;   }   template <class t>   ostream& operator<<(ostream& os, const vc<t>& v) {     os <<  { ;     for (auto e : v) os << e <<  , ;     return os <<  } ;   }   using uint = unsigned;   using ull = unsigned long long;   template <ll i, class T>   void print_tuple(ostream&, const T&) {}   template <ll i, class T, class H, class... Args>   void print_tuple(ostream& os, const T& t) {     if (i) os <<  , ;     os << get<i>(t);     print_tuple<i + 1, T, Args...>(os, t);   }   template <class... Args>   ostream& operator<<(ostream& os, const tuple<Args...>& t) {     os <<  { ;     print_tuple<0, tuple<Args...>, Args...>(os, t);     return os <<  } ;   }   void print(ll x, ll suc = 1) {     cout << x;     if (suc == 1) cout <<   n ;     if (suc == 2) cout <<    ;   }   ll read() {     ll i;     cin >> i;     return i;   }   vi readvi(ll n, ll off = 0) {     vi v(n);     for (ll i = ll(0); i < ll(n); i++) v[i] = read() + off;     return v;   }   template <class T>   void print(const vector<T>& v, ll suc = 1) {     for (ll i = ll(0); i < ll(v.size()); i++)       print(v[i], i == ll(v.size()) - 1 ? suc : 2);   }   string readString() {     string s;     cin >> s;     return s;   }   template <class T>   T sq(const T& t) {     return t * t;   }   void yes(bool ex = true) {     cout <<  Yes  << endl;     if (ex) exit(0);   }   void no(bool ex = true) {     cout <<  No  << endl;     if (ex) exit(0);   }   constexpr ll ten(ll n) { return n == 0 ? 1 : ten(n - 1) * 10; }   const ll infLL = LLONG_MAX / 3;   const ll inf = infLL;   ll topbit(signed t) { return t == 0 ? -1 : 31 - __builtin_clz(t); }   ll topbit(ll t) { return t == 0 ? -1 : 63 - __builtin_clzll(t); }   ll botbit(signed first) { return first == 0 ? 32 : __builtin_ctz(first); }   ll botbit(ll first) { return first == 0 ? 64 : __builtin_ctzll(first); }   ll popcount(signed t) { return __builtin_popcount(t); }   ll popcount(ll t) { return __builtin_popcountll(t); }   bool ispow2(ll i) { return i && (i & -i) == i; }   ll mask(ll i) { return (ll(1) << i) - 1; }   bool inc(ll first, ll second, ll c) { return first <= second && second <= c; }   template <class t>   void mkuni(vc<t>& v) {     sort(v.begin(), v.end());     v.erase(unique(v.begin(), v.end()), v.end());   }   ll rand_int(ll l, ll r) {     static random_device rd;     static mt19937_64 gen(rd());     return uniform_int_distribution<ll>(l, r)(gen);   }   ll gcd(ll first, ll second) {     return second ? gcd(second, first % second) : first;   }   ll lcm(ll first, ll second) { return first / gcd(first, second) * second; }   signed main() {     cin.tie(0);     ios::sync_with_stdio(0);     cout << fixed << setprecision(20);     ll n;     cin >> n;     ll g = 0;     vc<pi> vs;     for (ll _ = ll(0); _ < ll(n); _++) {       ll first, second;       cin >> first >> second;       g = gcd(g, lcm(first, second));       vs.emplace_back(first, second);     }     if (g > 1) {       for (auto z : vs) {         ll first = gcd(g, z.first);         ll second = gcd(g, z.second);         if (first > 1)           g = first;         else if (second > 1)           g = second;         else           assert(false);       }       cout << g << endl;     } else       cout << -1 << endl;   }