#include <iostream>
#include <vector>
#include <utility>
#include <algorithm>
using namespace std;
 
#define REP(i, n) for(ll i=0; i<n; i++)
#define FOR(i, a, b) for(ll i=a; i<=b; i++)
 
typedef long long ll;
 
const ll MX = 1e5;
const ll MY = 5*1e2;
const ll INF = 1e15;
 
vector<pair<ll, ll> >v;
 
 
int main()
{
        ll n;
        cin>>n;
        REP(i, n)
        {
                ll k, f;
                cin>>k>>f;
                v.push_back({k,f});
        }
        v.push_back({MX, 500});
        v.push_back({0, 0});
 
        sort(v.begin(), v.end());
        ll area=0;
        REP(i, v.size())
        {
                ll currlow = 500;
                FOR(j, i+1, v.size()-1)
                {
                        area = max(area, currlow*(v[j].first-v[i].first));
                        currlow = min(currlow, v[j].second);
                }
        }
 
        cout<<area<<endl;
} 

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NSAKMSA0IAoyIDMKMyAyCjUgMQo1IDIK

5 
1 4 
2 3
3 2
5 1
5 2