#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
istream &operator>>(istream &is, modint &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint &a) { return os << a.val(); }
istream &operator>>(istream &is, modint998244353 &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint998244353 &a) { return os << a.val(); }
istream &operator>>(istream &is, modint1000000007 &a) { long long v; is >> v; a = v; return is; }
ostream &operator<<(ostream &os, const modint1000000007 &a) { return os << a.val(); } 

typedef long long ll;
typedef vector<vector<int>> Graph;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define FOR(i,l,r) for (int i = l;i < (int)(r); i++)
#define rep(i,n) for (int i = 0;i < (int)(n); i++)
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define my_sort(x) sort(x.begin(), x.end())
#define my_max(x) *max_element(all(x))
#define my_min(x) *min_element(all(x))
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const int INF = (1<<30) - 1;
const ll LINF = (1LL<<62) - 1;
const int MOD = 998244353;
const int MOD2 = 1e9+7;
const double PI = acos(-1);
vector<int> di = {1,0,-1,0};
vector<int> dj = {0,1,0,-1};

#ifdef LOCAL
#  include <debug_print.hpp>
#  define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#  define debug(...) (static_cast<void>(0))
#endif

using S = pll;
using F = ll;
S op(S a, S b){
    if(a.first < b.first){
        return a;
    }
    else{
        return b;
    }
}
S e(){
    return make_pair(INF, INF);
}
S mapping(F f, S x){
    if(f == LINF) return x;
    return make_pair(x.second * f / __gcd(x.second, f), x.second);
}
F composition(F f, F g){
    return f;
}
F id(){
    return LINF;
}

int main(){
    cin.tie(0);
    ios_base::sync_with_stdio(false);
    int N; cin >> N;
    using P = tuple<ll,ll,ll>;
    vector<P> ABAB(N);
    rep(i,N){
        ll A, B; cin >> A >> B;
        ABAB[i] = P{A * B, A, B};
    }
    sort(rall(ABAB));

    lazy_segtree<S,op,e,F,mapping,composition,id> seg(vector<S>(N, make_pair(INF, INF)));

    ll ans = 0;
    rep(i,N){
        ll A = get<1>(ABAB[i]);
        ll B = get<2>(ABAB[i]);
        seg.apply(0, i, A);
        if(i){
            ll res = seg.prod(0, i).first;
            ans = max(ans, A * B / res - (A - 1) / res);
        }

        seg.set(i, S{A, A});
    }
    cout << ans << endl;
}