#include<bits/stdc++.h>

using namespace std;

const int N = 1e6+;

typedef long long ll;

int n;

int m;

ll ans;

struct data {

    ll l, r;

    data() {}

    data(ll _l, ll _r) : l(_l), r(_r) {}

    bool friend operator < (const data &a, const data &b) {

        return a.l == b.l ? a.r > b.r : a.l < b.l;

    }

} a[N], b[N];

ll calc(int i, int j)

{

    return (b[j].r - b[i].l)*(b[i].r - b[j].l);

}

void cdq(int l, int r, int L, int R)

{

    if(l > r) return;

    int mid = (l+r)>>, lim = min(R, mid-), p=mid;

    ll mx=;

    for(int i=lim; i>=L; --i)

    {

        ll tmp = calc(i, mid);

        if(tmp > mx)

        {

            p = i;

            mx = tmp;

        }

    }

    ans = max(ans, mx);

    cdq(l, mid - , L, p);

    cdq(mid + , r, p, R);

}

int main()

{

    scanf("%d", &n);

    for(int i = ; i <= n; ++i) scanf("%d%d", &a[i].l, &a[i].r);

    sort(a + , a + n + );

    int p = ;

    for(int i = ; i <= n; ++i) if(a[i].r > a[p].r) b[++m] = a[i], p = i;

    else ans = max(ans, (a[p].r - a[p].l) * (a[i].r - a[i].l));

    cdq(, m, , m);

    printf("%lld\n", ans);

    return ;

}