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

#define MAX_LINE_LENGTH 100

typedef struct Node {
    char text[MAX_LINE_LENGTH];
    struct Node *yes;
    struct Node *no;
} Node;

Node* create_node(const char* text) {
    Node *node = (Node*)malloc(sizeof(Node));
    if (!node) {
        fprintf(stderr, "Ошибка выделения памяти.\n");
        exit(1);
    }
    strncpy(node->text, text, MAX_LINE_LENGTH);
    node->yes = NULL;
    node->no = NULL;
    return node;
}

Node* parse_knowledge_base(char lines[][MAX_LINE_LENGTH], int *index, int line_count) {
    if (*index >= line_count || lines[*index][0] == '\0') {
        return NULL;
    }

    char *line = lines[*index];
    (*index)++;

    Node *node = NULL;
    if (line[0] == '*') {
        node = create_node(line + 1);
    } else {
        node = create_node(line);
        node->yes = parse_knowledge_base(lines, index, line_count);
        node->no = parse_knowledge_base(lines, index, line_count);
    }
    return node;
}

int is_valid_tree(Node* node) {
    if (!node) return 0;
    if ((!node->yes && node->no) || (node->yes && !node->no)) {
        return 0; // Некорректное состояние: одна ветка отсутствует
    }
    if (!node->yes && !node->no) {
        return 1; // Листовой узел
    }
    return is_valid_tree(node->yes) && is_valid_tree(node->no);
}

int count_products(Node *node) {
    if (!node) return 0;
    if (!node->yes && !node->no) return 1;
    return count_products(node->yes) + count_products(node->no);
}

void run_expert_system(Node *node) {
    int first_question = 1;

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

        if (!node->yes && !node->no) {
            printf("*%s\n", node->text);
            printf("Koniec\n");
            return;
        }

        printf("%s\n", node->text);

        char answer;
        if (scanf(" %c", &answer) != 1) {
            printf("Koniec vstupu\n");
            return;
        }

        if (answer == 'a') {
            node = node->yes;
        } else if (answer == 'n') {
            node = node->no;
        } else {
            printf("Nerozumiem\n");
            return;
        }
    }
}

void free_tree(Node *node) {
    if (node) {
        free_tree(node->yes);
        free_tree(node->no);
        free(node);
    }
}

int main() {
    char lines[100][MAX_LINE_LENGTH];
    int line_count = 0;

    while (fgets(lines[line_count], sizeof(lines[line_count]), stdin)) {
        lines[line_count][strcspn(lines[line_count], "\n")] = 0;
        if (lines[line_count][0] == '\0') {
            break;
        }
        line_count++;
    }

    if (line_count == 0) {
        printf("Expert z bufetu to vie.\n");
        printf("Chybna databaza\n");
        return 0;
    }

    int index = 0;
    Node *root = parse_knowledge_base(lines, &index, line_count);

    if (!root || !is_valid_tree(root)) {
        printf("Expert z bufetu to vie.\n");
        printf("Chybna databaza\n");
        free_tree(root);
        return 0;
    }

    printf("Expert z bufetu to vie.\n");
    int product_count = count_products(root);
    printf("Pozna %d druhov ovocia a zeleniny.\n", product_count);

    run_expert_system(root);

    free_tree(root);

    return 0;
}