#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef pair<ll, ll> p_ll;

template<class T>
void debug(T itr1, T itr2) { auto now = itr1; while(now<itr2) { cout << *now << " "; now++; } cout << endl; }
#define repr(i,from,to) for (ll i=(ll)from; i<(ll)to; i++)
#define all(vec) vec.begin(), vec.end()
#define rep(i,N) repr(i,0,N)
#define per(i,N) for (ll i=(ll)N-1; i>=0; i--)
#define popcount __builtin_popcount

const ll LLINF = pow(2,61)-1;
const ll INF = pow(2,30)-1;

ll gcd(ll a, ll b) { if (a<b) swap(a,b); return b==0 ? a : gcd(b, a%b); }
ll lcm(ll a, ll b) { return a/gcd(a,b)*b; }

int main() {
  ll N; cin >> N;
  ll A[2*N]; rep(i,2*N) cin >> A[i];
  ll result = 0; rep(i,N) result += A[i*2]*A[i*2+1];
  ll diff = 0; rep(i,N-1) diff = max(diff,(A[i*2+3]-A[i*2])*(A[i*2+1]-A[i*2+2]));
  result += diff;
  cout << result << endl;
  return 0;
}