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

#define SIZE 1024

struct Node {
    char value[SIZE];
    struct Node* left;
    struct Node* right;
};

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

struct Node* read_tree(void) {
    char buffer[SIZE] = {0};
    char* r = fgets(buffer, SIZE, stdin);
    if (r == NULL || buffer[0] == '\n' || buffer[0] == '\r') {
        return NULL;
    }
    struct Node* node = calloc(1, sizeof(struct Node));
    if (node == NULL) return NULL;
    memcpy(node->value, buffer, SIZE);

    if (buffer[0] != '*') {
        node->left = read_tree();
        if (node->left == NULL) {
            destroy_tree(node);
            return NULL;
        }
        node->right = read_tree();
        if (node->right == NULL) {
            destroy_tree(node);
            return NULL;
        }
    }
    return node;
}

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

void run_system(struct Node* node) {
    if (node == NULL) return;
    printf("%s", node->value);

    if (node->left == NULL && node->right == NULL) {
        printf("End\n");
        return;
    }
    char answer[SIZE];
    if (fgets(answer, SIZE, stdin) == NULL) return;
    answer[strcspn(answer, "\r\n")] = '\0';

    if (strcmp(answer, "y") == 0) {
        run_system(node->left);
    } else if (strcmp(answer, "n") == 0) {
        run_system(node->right);
    } else {
        printf("I don't understand\n");
    }
}

int main(void) {
    struct Node* root = read_tree();
    if (root == NULL) {
        printf("Error: failed to load the rule base.\n");
        return 1;
    }
    char sep[SIZE];
    if (fgets(sep, SIZE, stdin) == NULL || (sep[0] != '\n' && sep[0] != '\r')) {
        printf("Error: missing blank separator line.\n");
        destroy_tree(root);
        return 1;
    }
    int leaves = count_leaves(root);
    printf("The Expert System is ready.\n");
    printf("It knows %d types of fruits and vegetables.\n", leaves);
    printf("Answer 'y' (yes) or 'n' (no)\n");

    run_system(root);
    destroy_tree(root);

    return 0;
}