diff --git a/cv8/program.c b/cv8/program.c
index f65d4d0..3a55f0a 100644
--- a/cv8/program.c
+++ b/cv8/program.c
@@ -63,6 +63,10 @@ void ask(struct node* tree){
         return;
     }
     r = fgets(buff, SIZE, stdin);
+     if(r == NULL){
+        puts("Koniec vstupu");
+        return;
+    }
     if(r[0] == 'a' && tree->left != NULL){
         tree = tree->left;
         ask(tree);