// OJI 2025 11-12 Ivan Andrei
// Aventura 19 Subtask 2
#include <bits/stdc++.h> 
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
  
#pragma GCC optimize("O3") 
#pragma GCC optimize("unroll-loops") 
#pragma GCC target("avx2") 
  
using namespace std; 
using namespace __gnu_pbds; 
  
#define ordered_set tree<long long, null_type, less<long long>, rb_tree_tag, tree_order_statistics_node_update> 
#define lsb(x) (x & (-x)) 
  
const long long mod = 1e9 + 7, max_size = 5e3 + 20, INF = 2e9 + 2; 

int v[max_size], dp[max_size], nxt[max_size];

void solve() 
{
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        cin >> v[i];
        dp[i] = INF;
        nxt[i] = n + 1;
    }
    int mx = 0;
    for (int i = n; i > 0; i--)
    {
        int mn = INF;
        for (int j = i + 1; j <= n; j++)
        {
            if (v[j] < v[i])
            {
                continue;
            }
            if (v[j] < mn)
            {
                if (dp[j] + 1 < dp[i])
                {
                    nxt[i] = j;
                }
                mn = v[j];
            }
        }
        dp[i] = dp[nxt[i]] + 1;
        mx = max(mx, dp[i]);
    }
    cout << mx << '\n';
}
  
signed main() 
{ 
#ifdef LOCAL 
    freopen("test.in", "r", stdin); 
    freopen("test.out", "w", stdout); 
#else 
    freopen("subsir2.in", "r", stdin); 
    freopen("subsir2.out", "w", stdout); 
#endif // LOCAL 
    ios_base::sync_with_stdio(false); 
    cin.tie(0); 
    cout.tie(0); 
    long long tt; 
    //cin >> tt; 
    tt = 1; 
    while (tt--) 
    { 
        solve(); 
    } 
    return 0; 
}