#include <bits/stdc++.h>

using namespace std;

struct node
{
    int key;
    node *l, *r;
};

int in(node* root, node* el, int h)
{
    if (root->l && root->key > el->key)
        return in(root->l, el, h) + 1;
    if (root->r && root->key < el->key)
        return in(root->r, el, h) + 1;
    if (root->key > el->key)
    {
        root->l = el;
        return h + 1;
    }
    if (root->key < el->key)
    {
        root->r = el;
        return h + 1;
    }
}

int main()
{
//    freopen("A.in", "r", stdin);

    int f;
    cin >> f;

    if (f == 0)
        cout << 0;
    else
    {
        node *root = new node;
        root->l = root->r = nullptr;
        root->key = f;

        int ans = 0;

        while(cin)
        {
            int curr;
            cin >> curr;

            if (curr == 0)
                break;

            node *el = new node;
            el->l = el->r = nullptr;
            el->key = curr;

            int h = 0;
            ans = max(in(root, el, 1), ans);
        }

        cout << ans;
    }
}