#include <stdio.h>
#include <stdlib.h>
#define max(a,b)  (a>b)? a : b
typedef struct tree{
    struct tree *left;
    struct tree *right;
    int value;
    char balance_factor;
}tree;
tree * right_rotation(tree* in)
{
    tree*x=in->left;
    in->left=in->left->right;
    x->right=in;
    return x;

}
tree * left_rotation(tree* in)
{
    tree*x=in->right;
    in->right=in->right->left;
    x->left=in;
    return x;

}
tree * rightleft_rotation (tree* in)
{
    in->right=right_rotation(in->right);
    in=left_rotation(in);
    return in;
}
tree * leftright_rotation (tree* in)
{
    in->left=left_rotation(in->left);
    in=right_rotation(in);
    return in;
}
tree * tree_balance(tree* in)
{

    if (in->balance_factor==2&&in->left->balance_factor==1) {
       // printf("ty loh rl"); //когда вставили в левое поддерево левого поддерева
        in=right_rotation(in);
        return in;
    }
    if (in->balance_factor==2&&in->left->balance_factor==-1) {
       // printf("ty loh lr"); //когда вставили в правое поддерево левого поддерева
        in=leftright_rotation(in);
        return in;
    }
    if (in->balance_factor==-2&&in->right->balance_factor==-1) {
     //   printf("ty loh r");  //когда вставили в правое поддерево правого поддерева
        in=left_rotation(in);
        return in;
    }
    if (in->balance_factor==-2&&in->right->balance_factor==1) {
     //   printf("ty loh rl");  //когда вставили в левое поддерево правого поддерева
        in=rightleft_rotation(in);
        return in;
    }
}
tree *add_element(tree *in_tree,int addvalue)
{
    tree* x;
    x=(tree*)malloc(sizeof(tree));
    x->value=addvalue;
    x->left=NULL;
    x->right=NULL;
    x->balance_factor=0;
    if (in_tree==NULL) {
        in_tree=x;
    }
    else {
            if (addvalue>in_tree->value)
               in_tree->right= add_element(in_tree->right,addvalue);
            else
               in_tree->left= add_element(in_tree->left,addvalue);
    }
    in_tree->balance_factor=tree_height(in_tree->left)-tree_height(in_tree->right);
    if (in_tree->balance_factor>1||in_tree->balance_factor<-1) in_tree=tree_balance(in_tree);
    //printf("%d\n",in_tree->balance_factor);
    return in_tree;
}
void obhod (tree* in)
{
    if (in) {
        printf("%d ",in->value);
        obhod(in->left);
        obhod(in->right);
    }
}
int tree_height (tree* in)
{
    return (!in) ? 0 : (max (tree_height(in->left),tree_height(in->right)))+1;
}
int main()
{
    FILE *fin,*fout;
    fin=fopen("in.txt","r");
    tree *new_tree= NULL;
    int numbers,i,vertex;
    fscanf(fin,"%d",&numbers);
    for(i=0;i<numbers;i++) {
            fscanf(fin,"%d",&vertex);
            new_tree=add_element(new_tree,vertex);
           // printf("%d ",new_tree->value);
    }
    //obhod(new_tree);
    printf("%d",tree_height(new_tree));
    return 0;
}