#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_SIZE 256

struct node {
    char value[MAX_SIZE];
    struct node *left;
    struct node *right;
    int id;
};

struct node* read_tree(int *id_counter) {
    char line[MAX_SIZE];

    if (fgets(line, MAX_SIZE, stdin) == NULL || line[0] == '\n') {
        return NULL; 
    }

    struct node *new_node = (struct node*)malloc(sizeof(struct node));
    if (new_node == NULL) {
        return NULL; 
    }

    strcpy(new_node->value, line);
    new_node->id = (*id_counter)++;

    if (line[0] != '*') {
        new_node->left = read_tree(id_counter);
        new_node->right = read_tree(id_counter);
    }

    return new_node;
}

void free_tree(struct node *root) {
    if (root == NULL) return;
    free_tree(root->left);
    free_tree(root->right);
    free(root);
}

int count_items(struct node *root) {
    if (root == NULL) return 0;
    if (root->left == NULL && root->right == NULL) return 1;
    return count_items(root->left) + count_items(root->right);
}

void start_system(struct node *current_node) {
    if (current_node == NULL) return;

    int blank_lines = 0;
    int is_first_prompt = 1;

    while (current_node != NULL) {
        if (current_node->left == NULL && current_node->right == NULL) {
            printf("%s", current_node->value);
            printf("Koniec\n");
            return;
        }

        if (is_first_prompt) {
            printf("Odpovedajte 'a' pre prvu moznost alebo 'n' pre druhu moznost.\n");
            is_first_prompt = 0;
        }

        printf("%s", current_node->value);

        char response;
        int result = scanf(" %c", &response);

        if (result == EOF || (response == '\n' && ++blank_lines >= 2)) {
            printf("Koniec vstupu\n");
            return;
        }

        if (response == 'a') {
            blank_lines = 0;
            current_node = current_node->left;
        } else if (response == 'n') {
            blank_lines = 0;
            current_node = current_node->right;
        } else {
            printf("Nerozumiem\n");
            return;
        }
    }
}

int main() {
    int counter = 0;
    struct node *root = read_tree(&counter);

    printf("Expert z bufetu to vie.\n");

    if (root == NULL) {
        printf("Chybna databaza\n");
        return 0; 
    }

    int item_count = count_items(root);
    printf("Pozna %d druhov ovocia a zeleniny.\n", item_count);

    start_system(root);
    free_tree(root);

    return 0;
}