#include <iostream>
#include <cstdio>
#include <cassert>
#include <cstring>
#include <vector>
#include <valarray>
#include <array>
#include <queue>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <algorithm>
#include <cmath>
#include <complex>
#include <random>

using namespace std;
typedef long long ll;


/**
 * 遅延評価で書かれているStarry Sky Tree
 */
template <int S>
struct StarrySkyTree {
    typedef pair<int, int> D;
    static const int N = 1<<S;
    D seg[2*N][2], lz[2*N][2];
    int sz[2*N];
    StarrySkyTree() {
        for (int i = 2*N-1; i >= N; i--) {
            sz[i] = 1;
        }
        for (int i = N-1; i >= 1; i--) {
            sz[i] = sz[i*2]+sz[i*2+1];
        }
    }
    int base;
    void init(int b) {
    	base = b;
        for (int i = 1; i < 2*N; i++) {
        	seg[i][0] = seg[i][1] = D(0, base);
        }
    }

    void lzdata(int k, D x) {
    	if (x > seg[k][0]) {
    		swap(x, seg[k][0]);
    	}
    	if (x.second == seg[k][0].second) return;
    	if (x > seg[k][1]) {
    		swap(x, seg[k][1]);
    	}
    }
    void push(int k) {
        assert(1 <= k && k < N);
        if (seg[k][0].first >= 1) {
            lzdata(k*2, seg[k][0]);
            lzdata(k*2+1, seg[k][0]);
            seg[k][0] = D(0, base);
        }
        if (seg[k][1].first >= 1) {
            lzdata(k*2, seg[k][1]);
            lzdata(k*2+1, seg[k][1]);
            seg[k][1] = D(0, base);
        }
    }
    void update(int k) {
        assert(1 <= k && k < N);
    }

    pair<D, D> get(int k) {
        k += N;
        for (int i = S; i > 0; i--) {
            push(k>>i);
        }
        return make_pair(seg[k][0], seg[k][1]);
    }

    void set(int a, int b, D x, int k = 1) {
        if (sz[k] <= a || b <= 0) return;
        if (a <= 0 && sz[k] <= b) {
            lzdata(k, x);
            return;
        }
        push(k);
        set(a, b, x, k*2);
        set(a-sz[k]/2, b-sz[k]/2, x, k*2+1);
        update(k);
    }
};

const int MN = 100100;
int a[MN];

StarrySkyTree<17> st1, st2;

int main() {
	int n;
	cin >> n;
	vector<int> v;
	for (int i = 0; i < n; i++) {
		cin >> a[i];
		v.push_back(a[i]);
	}
	sort(v.begin(), v.end());
	v.erase(unique(v.begin(), v.end()), v.end());
	for (int i = 0; i < n; i++) {
		a[i] = lower_bound(v.begin(), v.end(), a[i]) - v.begin();
	}
	st1.init(-1); st2.init(n);
	int res = 0;
	for (int i = 0; i < n; i++) {
		//up
		auto x = st1.get(a[i]);
		{	
			auto y = x.first;
			y.first++;
			res = max(res, y.first);
			auto u = y.second; y.second = a[i];
			st2.set(0, u, y);
			st2.set(u+1, a[i], y);
		}
		{	
			auto y = x.second;
			y.first++;
			res = max(res, y.first);
			auto u = y.second; y.second = a[i];
			st2.set(0, u, y);
			st2.set(u+1, a[i], y);
		}
		x = st2.get(a[i]);
		{	
			auto y = x.first;
			y.first++;
			res = max(res, y.first);
			auto u = y.second; y.second = a[i];
			st1.set(a[i]+1, u, y);
			st1.set(u+1, n, y);
		}
		{	
			auto y = x.second;
			y.first++;
			res = max(res, y.first);
			auto u = y.second; y.second = a[i];
			st1.set(a[i]+1, u, y);
			st1.set(u+1, n, y);
		}
	}
	if (res <= 2) res = 0;
	cout << res << endl;
    return 0;
}