#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#define SIZE 100

struct tree {
    char* value;
    struct tree* left;
    struct tree* right;
};

struct tree* read_tree(){  
    char buffer[SIZE];  
    memset(buffer, 0, SIZE);  
    char* r = fgets(buffer, SIZE, stdin);  
    if(buffer[0] == '\n'){
        return NULL;    
    }
    assert(r); 
    struct tree* node = calloc(1, sizeof(struct tree)); 
    node->value = malloc(strlen(buffer) + 1);
    assert(node->value); 
    node->left = read_tree();
    node->right = read_tree();
    return node;  
} 

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

int main(){
    struct tree* root = read_tree();
    read_tree(); 
    destroy_tree(root);
    return 0;
}