#ifdef LOCAL
    #define _GLIBCXX_DEBUG
    #define __clock__
#else
    #pragma GCC optimize("Ofast")
#endif
#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using VI = vector<ll>;
using VV = vector<VI>;
using VS = vector<string>;
using PII = pair<ll, ll>;

// tourist set
template <typename A, typename B>
string to_string(pair<A, B> p);

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p);

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p);

string to_string(const string& s) {
  return '"' + s + '"';
}

string to_string(const char* s) {
  return to_string((string) s);
}

string to_string(bool b) {
  return (b ? "true" : "false");
}

string to_string(char c){
  string s = {c};
  return s;
}

string to_string(vector<bool> v) {
  bool first = true;
  string res = "{";
  for (int i = 0; i < static_cast<int>(v.size()); i++) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(v[i]);
  }
  res += "}";
  return res;
}

template <size_t N>
string to_string(bitset<N> v) {
  string res = "";
  for (size_t i = 0; i < N; i++) {
    res += static_cast<char>('0' + v[i]);
  }
  return res;
}

template <typename A>
string to_string(A v) {
  bool first = true;
  string res = "{";
  for (const auto &x : v) {
    if (!first) {
      res += ", ";
    }
    first = false;
    res += to_string(x);
  }
  res += "}";
  return res;
}

template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ", " + to_string(p.second) + ")";
}

template <typename A, typename B, typename C>
string to_string(tuple<A, B, C> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ")";
}

template <typename A, typename B, typename C, typename D>
string to_string(tuple<A, B, C, D> p) {
  return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")";
}

void debug_out() { cerr << '\n'; }

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cerr << " " << to_string(H);
  debug_out(T...);
}

#ifdef LOCAL
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif
// tourist set end

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; }

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define rep(i,b) FOR(i, 0, b)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<'\n'
#define p2(s, t) cout << (s) << " " << (t) << '\n'
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << '\n'
#define SZ(x) ((int)(x).size())
#define SORT(A) sort(ALL(A))
#define RSORT(A) sort(ALL(A), greater<ll>())
#define p_yes() p("Yes")
#define p_no() p("No")
#define possible() p("Possible")
#define impossible() p("Impossible")

ll SUM(VI& V){
  return accumulate(ALL(V), 0LL);
}

ll MIN(VI& V){return *min_element(ALL(V));}
ll MAX(VI& V){return *max_element(ALL(V));}

void print_vector(VI& V, ll offset=0){
  ll n = V.size();
  rep(i, n){
    if(i) cout << ' ';
    cout << V[i]+offset;
  }
  cout << endl;
}

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;
}

// long double
using ld = long double;
#define EPS (1e-14)
#define equals(a,b) (fabs((a)-(b)) < EPS)

// 小さい順に取り出すpriority queue
using inverse_priority_queue = priority_queue<ll, vector<ll>, greater<ll> >;

int popcount(ll t){
    return __builtin_popcountll(t);
}

void no(){p_no(); exit(0);}
void yes(){p_yes(); exit(0);}

const ll mod = 1e9 + 7;
// const ll mod = 998244353;
const ll inf = 1e18;
const double PI = acos(-1);

// [a/b] (繰り上げ)
ll ceil_div(ll a, ll b){
  return (a+b-1)/b;
}

ll string_to_ll(string s){
  return atoll(s.c_str());
}

// snuke's mint
// auto mod int
// https://youtu.be/L8grWxBlIZ4?t=9858
// https://youtu.be/ERZuLAxZffQ?t=4807 : optimize
// https://youtu.be/8uowVvQ_-Mo?t=1329 : division
// const int mod = 1000000007;
struct mint {
  ll x; // typedef long long ll;
  mint(ll x=0):x((x%mod+mod)%mod){}
  mint operator-() const { return mint(-x);}
  mint& operator+=(const mint a) {
    if ((x += a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator-=(const mint a) {
    if ((x += mod-a.x) >= mod) x -= mod;
    return *this;
  }
  mint& operator*=(const mint a) {
    (x *= a.x) %= mod;
    return *this;
  }
  mint operator+(const mint a) const {
    mint res(*this);
    return res+=a;
  }
  mint operator-(const mint a) const {
    mint res(*this);
    return res-=a;
  }
  mint operator*(const mint a) const {
    mint res(*this);
    return res*=a;
  }
  mint pow(ll t) const {
    if (!t) return 1;
    mint a = pow(t>>1);
    a *= a;
    if (t&1) a *= *this;
    return a;
  }

  // for prime mod
  mint inv() const {
    return pow(mod-2);
  }
  mint& operator/=(const mint a) {
    return (*this) *= a.inv();
  }
  mint operator/(const mint a) const {
    mint res(*this);
    return res/=a;
  }
};

#include <atcoder/math>
using namespace atcoder; // 忘れがち

// 計算量O(√N)
// なのでN=10^18だと間に合いません

// 素因数分解
// その素因数が何個あるかのmapを返す
map<ll, ll> factorize(ll n){
    map<ll, ll> mp;
    ll sq = sqrt(n);
    FOR(i, 2, sq+1){
        while(n%i==0){
            mp[i]++;
            n/=i;
        }
    }
    // 残り
    if(n!=1){
        mp[n]++;
    }
    return mp;
}

// 約数の種類数
// 6 => 1, 2, 3, 6なので4
ll yaku(ll n){
  auto mp = factorize(n);
  ll ret = 1;
  for(auto pa : mp){
    ret *= (pa.second+1);
  }
  return ret;
}

// 約数一覧を返します
vector<ll> calc_devisors(ll a){
    vector<ll> ret;
    for(ll i=1; i*i<=a; i++){
        if(a%i!=0) continue;
        ret.push_back(i);
        ll another = a/i;
        if(i!=another) ret.push_back(another);
    }
    sort(ALL(ret), greater<ll>()); // 使いやすいように大きい順にソートしておく
    return ret;
}

ll ll_pow(ll a, ll n){
    ll ans = 1;
    FOR(i, 0, n){
        ans *= a;
    }
    return ans;
}
// modなし

// Yiが互いに素になるように1番大きいものだけ残してからACLのCRT使ってみたが
// それではまだ不足でoverflowするコードです

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    ll N;cin>>N;
    VI X(N);
    VI Y(N);
    rep(i,N){
      cin>>X[i]>>Y[i];
    }

    // lcmが大きくならないように調整
    
    // prime => cnt,idx
    map<ll,PII> so;

    vector<map<ll,ll>> MP(N);
    rep(i,N){
      MP[i] = factorize(Y[i]);
      debug(MP[i]);
      for(auto pa : MP[i]){
        ll v = pa.first;
        ll c = pa.second;
        if(so[v].first<c){
          so[v]={c,i};
        }
      }
    }

    debug(Y);
    rep(i,N){
      ll y=1;
      for(auto pa : MP[i]){
        ll v = pa.first;
        ll c = pa.second;
        if(so[v].second==i){
          y *= ll_pow(v,c);
        }
      }
      Y[i]=y;
      X[i] %= y;
    }
    debug(Y);

    VI R = X;
    VI M = Y;
    auto pa = crt(R,M);
    if(pa.second==0){
      p(-1);return 0;
    }
    ll ans = pa.first;
    if(ans==0)ans+=pa.second;
    ans %= mod;
    p(ans);
    
    return 0;
}