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#include <iostream>
#include <vector>
#include <stack>
#include <queue>

using namespace std;

vector<int> find_next_index(const vector<int> &nums)
{
    int n = nums.size();
    vector<int> result(n, -1);
    stack<int> s;

    for (int i = 0; i < 2 * n; ++i)
    {
        int current_idx = i % n;
        int current_val = nums[current_idx];

        while (!s.empty() && current_val > nums[s.top()])
        {
            int smaller_index = s.top();
            s.pop();
            result[smaller_index] = current_idx;
        }

        if (i < n)
        {
            s.push(current_idx);
        }
    }

    return result;
}

int count_topological_layers(const vector<int> &data)
{
    int n = data.size();
    vector<vector<int>> adj(n);
    vector<int> in_degree(n, 0);

    for (int i = 0; i < n; ++i)
    {
        int target = data[i];
        if (target != -1)
        {
            adj[i].push_back(target);
            in_degree[target]++;
        }
    }

    queue<int> q;
    for (int i = 0; i < n; ++i)
    {
        if (in_degree[i] == 0)
        {
            q.push(i);
        }
    }

    int layers = 0;
    while (!q.empty())
    {
        layers++;
        int level_size = q.size();

        for (int i = 0; i < level_size; ++i)
        {
            int current = q.front();
            q.pop();

            for (int neighbor : adj[current])
            {
                in_degree[neighbor]--;
                if (in_degree[neighbor] == 0)
                {
                    q.push(neighbor);
                }
            }
        }
    }

    return layers;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int n;
    cin >> n;

    vector<int> a(n);

    for (int i = 0; i < n; ++i)
    {
        cin >> a[i];
    }

    vector<int> next_indices = find_next_index(a);
    cout << count_topological_layers(next_indices) << endl;

    return 0;
}