#include <bits/stdc++.h>

using namespace std;

#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, a, b) for(int i = (a) - 1; i >= (b); i--)
#define SZ(a) int(a.size())
#define ALL(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair
#define F first
#define S second

typedef long long LL;
typedef vector<int> VI;
typedef vector<LL> VL;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
typedef double db;

struct DSU
{
	int n;
	VI p, sz;
	
	DSU(int _n = 0) 
	{
		n = _n;
		p.resize(n);
		iota(ALL(p), 0);
		sz.assign(n, 1);
	}
	int find(int v)
	{
		if (v == p[v])
			return v;
		return p[v] = find(p[v]);
	}
	bool unite(int u, int v)
	{
		u = find(u);
		v = find(v);
		if (u == v) 
			return false;
		if (sz[u] > sz[v])
			swap(u, v);
		p[u] = v;
		sz[v] += sz[u];
		return true;
	}
};

const int N = 1047;
int r[N][N];
int c[N][N];

int main()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	
	int n;
	cin >> n;
	int x, y;
	cin >> x >> y;
	x++, y++;
	FOR (it, 0, n)
	{
		int x2, y2;
		cin >> x2 >> y2;
		x2++, y2++;
		if (x == x2)
		{
			FOR (i, min(y, y2), max(y, y2))
				c[i][x] = 1;
		}
		else
		{
			FOR (i, min(x, x2), max(x, x2))
				r[y][i] = 1;			
		}
		x = x2;
		y = y2;
	}
	DSU d(N * N);
	FOR (i, 1, N)
	{
		FOR (j, 1, N)
		{
			int f1 = i * N + j;
			if (!c[i][j])
				d.unite(f1, i * N + j - 1);
			if (!r[i][j])
				d.unite(f1, i * N + j - N);
		}	
	}
	int ans = 0;
	FOR (i, 1, N)
	{
		FOR (j, 1, N)
			if (d.find(i * N + j) != d.find(1))
				ans = max(ans, d.sz[d.find(i * N + j)]);
	}
	cout << ans << '\n';
	
	return 0;
}