diff --git a/cv7/program.c b/cv7/program.c
index 266a371..ce7a8a8 100644
--- a/cv7/program.c
+++ b/cv7/program.c
@@ -1,6 +1,5 @@
 #include <stdio.h>
 #include <string.h>
-#include <assert.h>
 #include <stdlib.h>
 
 #define SIZE 100
@@ -11,6 +10,8 @@ struct tree {
     struct tree* right;
 };
 
+int error_flag = 0;
+
 struct tree* read_tree() {
     char buffer[SIZE];
     memset(buffer, 0, SIZE);
@@ -20,6 +21,11 @@ struct tree* read_tree() {
     }
     buffer[strcspn(buffer, "\n")] = 0;
     struct tree* node = calloc(1, sizeof(struct tree));
+    if (buffer[0] == '*') {
+        if (strlen(buffer) <= 1) {
+            error_flag = 1;
+        }
+    }
     strncpy(node->value, buffer, SIZE - 1);
     return node;
 }
@@ -29,7 +35,7 @@ struct tree* load_tree() {
     if (!node) {
         return NULL;
     }
-    if (node->value[0] != '*') {
+    if (error_flag || node->value[0] != '*') {
         node->left = load_tree();
         node->right = load_tree();
     }
@@ -65,16 +71,18 @@ void run_tree(struct tree* tree) {
 }
 
 void destroy_tree(struct tree* tree) {
-    if (tree->left != NULL) {
-        destroy_tree(tree->left);
-    }
-    if (tree->right != NULL) {
-        destroy_tree(tree->right);
+    if (!tree) {
+        return;
     }
+    destroy_tree(tree->left);
+    destroy_tree(tree->right);
     free(tree);
 }
 
 void count_items(struct tree* tree, int* count) {
+    if (!tree) {
+        return;
+    }
     if (tree->left == NULL && tree->right == NULL) {
         (*count)++;
     } else {
@@ -86,8 +94,9 @@ void count_items(struct tree* tree, int* count) {
 int main() {
     struct tree* root = load_tree();
     printf("Expert z bufetu to vie.\n");
-    if (!root) {
+    if (!root || error_flag) {
         printf("Chybna databaza\n");
+        destroy_tree(root);
         return 0;
     }