u302-i

#include <stdio.h>
#include <string.h>
#include <algorithm>
#include <vector>
#include <set>
using namespace std;
#define mk make_pair
#define pb push_back
const int maxn = 222222;
const int inf = 1e9;
int n;
int x, p[maxn];
int up[maxn], down[maxn];
int derevo[maxn<<2];
int num;
int getmax(int l, int r){
    l = num + l - 1;
    r = num + r - 1;
    int res = 0;
    while(l <= r){
        if(l % 2){
            if(derevo[l] > res) res = derevo[l];
            l ++;
        }
        if(r % 2 == 0){
            if(derevo[r] > res) res = derevo[r];
            r --;
        }
        l >>= 1;
        r >>= 1;
    }
    return res;
}
void update(int pos, int val){
    pos = num + pos - 1;
    derevo[pos] = val;
    pos >>= 1;
    while(pos >= 1){
        derevo[pos] = max(derevo[pos << 1], derevo[pos<<1|1]);
        pos >>= 1;
    }
}
int main(){
    freopen("improvements.in","r",stdin);
    freopen("improvements.out","w",stdout);
    scanf("%d",&n);
    for(int i = 1; i <= n; i ++){
        scanf("%d",&x);
        p[x] = i;
    }
    num = 1;
    while(num <= n) num <<= 1;
    for(int i = 1; i <= n; i ++){
        int current = p[i];
        int cr = 1 + getmax(1,current - 1);
        up[i] = max(up[i-1], cr);
        update(current, cr);
    }
    memset(derevo, 0, sizeof derevo);
    for(int i = n; i > 0; i--){
        int current = p[i];
        int cr = 1 + getmax(1,current - 1);
        down[i] = max(down[i+1], cr);
        update(current, cr);
    }
    int ans = min(up[n],down[1]);
    for(int i = 1; i < n; i ++) ans = max(ans, up[i] + down[i + 1]);
    printf("%d\n", ans);
   return 0;
}