#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <complex>
#include <string>
#include <sstream>
#include <algorithm>
#include <numeric>
#include <vector>
#include <queue>
#include <stack>
#include <functional>
#include <iostream>
#include <map>
#include <set>
#include <cassert>
using namespace std;
typedef pair<int,int> P;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
#define pu push
#define pb push_back
#define mp make_pair
#define eps 1e-9
#define INF 2000000000
#define sz(x) ((int)(x).size())
#define fi first
#define sec second
#define SORT(x) sort((x).begin(),(x).end())
#define all(x) (x).begin(),(x).end()
#define rep(i,n) for(int (i)=0;(i)<(int)(n);(i)++)
#define repn(i,a,n) for(int (i)=(a);(i)<(int)(n);(i)++)
#define EQ(a,b) (abs((a)-(b))<eps)
struct Data{
	int len,l,m;
	Data():len(0),l(-1),m(-1){}
	Data(int len,int l,int m):len(len),l(l),m(m){}
};
bool comp(Data a,Data b){
	if(a.len!=b.len)return a.len > b.len;
	if(a.l!=b.l)return a.l > b.l;
	return a.m < b.m;
}
typedef pair<Data,Data> PD;
void print(PD x){
	printf("len %d l %d m %d\n",x.fi.len,x.fi.l,x.fi.m);
	printf("len %d l %d m %d\n",x.sec.len,x.sec.l,x.sec.m);
}
Data input_data(){
	Data res;
	scanf("%d %d %d",&(res.len),&(res.l),&(res.m));
	return res;
}
PD upd(PD a,PD b,int f){
	vector<Data> v;
	v.pb(a.fi);v.pb(a.sec);
	if(b.fi.l!=f)v.pb(Data(b.fi.len+1,b.fi.m,f));
	if(b.fi.len!=0&&b.sec.l!=f)v.pb(Data(b.sec.len+1,b.sec.m,f));
	sort(all(v),comp);
	PD res;
	res.fi = v[0];
	int id = 1;
	while(id<(int)v.size()&&v[id].l==v[0].l)id++;
	res.sec = v[id];
	return res;
}
PD merge(PD a,PD b){
	vector<Data> v;
	v.pb(a.fi);v.pb(a.sec);v.pb(b.fi);v.pb(b.sec);
	sort(all(v),comp);
	PD res;
	res.fi = v[0];
	int id = 1;
	while(id<(int)v.size()&&v[id].l==v[0].l)id++;
	res.sec = v[id];
	return res;
}
const int SIZE = 1<<17;
struct segtree{
	PD seg[SIZE*2];
	segtree(){
		for(int i=0;i<SIZE*2-1;i++)seg[i]=PD(Data(0,-1,-1),Data(0,-2,-2));
	}
	void show(){
		for(int i=SIZE-1;i<SIZE*2-1;i++){
			printf("%d\n",i-SIZE+1);
			print(seg[i]);
		}
	}
	void update(int k,PD x){
		int idx = k+SIZE-1;
		seg[idx]=upd(seg[idx],x,k);
		while(idx){
			idx = (idx-1)/2;
			seg[idx]=merge(seg[idx*2+1],seg[idx*2+2]);
		}
	}
	PD query(int a,int b){
		return query(a,b,0,0,SIZE);
	}
	PD query(int a,int b,int k,int l,int r){
		if(a>=b)return PD(Data(0,-1,-1),Data(0,-2,-2));
		if(r<=a||b<=l)return PD(Data(0,-1,-1),Data(0,-2,-2));
		else if(a<=l&&r<=b)return seg[k];
		else{
			PD lch = query(a,b,k*2+1,l,(l+r)/2);
			PD rch = query(a,b,k*2+2,(l+r)/2,r);
			return merge(lch,rch);
		}
	}
};
segtree up,down;
int N,M,A[100100];
vector<int> vs;
int main(){
	/*while(1){
		PD a,b;
		a.fi = input_data();
		a.sec = input_data();
		b.fi = input_data();
		b.sec = input_data();
		print(merge(a,b));
	}*/
	scanf("%d",&N);
	for(int i=0;i<N;i++){
		scanf("%d",&A[i]);
		vs.pb(A[i]);
	}
	sort(all(vs));
	vs.erase(unique(all(vs)),vs.end());
	M = (int)vs.size();
	for(int i=0;i<N;i++)A[i]=lower_bound(all(vs),A[i])-vs.begin();
	//for(int i=0;i<M;i++)printf("%d%c",vs[i],(i==M-1)?'\n':' ');
	for(int i=0;i<N;i++){
		/*int a;
		scanf("%d",&a);
		printf("down:\n");
		down.show();
		printf("up:\n");
		up.show();*/
		
		PD rd,ri,tmp;
		
		tmp = down.query(0,A[i]);
		if(tmp.fi.l!=A[i])rd.fi=tmp.fi;
		else rd.fi = tmp.sec;
		tmp = down.query(0,rd.fi.m);
		if(tmp.fi.l!=A[i])rd.sec=tmp.fi;
		else rd.sec=tmp.sec;
		tmp = down.query(rd.fi.m+1,A[i]);
		if(tmp.fi.l!=A[i]&&tmp.fi.len>rd.sec.len)rd.sec=tmp.fi;
		if(tmp.sec.l!=A[i]&&tmp.sec.len>rd.sec.len)rd.sec=tmp.sec;
		
		tmp = up.query(A[i]+1,M);
		/*printf("tmp1:\n");
		print(tmp);*/
		if(tmp.fi.l!=A[i])ri.fi=tmp.fi;
		else ri.fi = tmp.sec;
		tmp = up.query(A[i]+1,ri.fi.m);
		/*printf("tmp2:\n");
		print(tmp);*/
		if(tmp.fi.l!=A[i])ri.sec=tmp.fi;
		else ri.sec=tmp.sec;
		tmp = up.query(ri.fi.m+1,M);
		/*printf("tmp3:\n");
		print(tmp);*/
		if(tmp.fi.l!=A[i]&&tmp.fi.len>ri.sec.len)ri.sec=tmp.fi;
		if(tmp.sec.l!=A[i]&&tmp.sec.len>ri.sec.len)ri.sec=tmp.sec;
		
		/*printf("rd:\n");
		print(rd);
		printf("ri:\n");
		print(ri);*/
		up.update(A[i],rd);
		down.update(A[i],ri);
	}
	int ans = (down.query(0,M)).fi.len;
	ans = max(ans,(up.query(0,M)).fi.len);
	if(ans<3)ans = 0;
	printf("%d\n",ans);
	return 0;
}