diff --git a/cv7/program.c b/cv7/program.c
index 61cc1d4..c056c10 100644
--- a/cv7/program.c
+++ b/cv7/program.c
@@ -14,7 +14,7 @@ struct tree {
 struct tree* read_tree() {
     char buffer[SIZE];
     if (fgets(buffer, SIZE, stdin) == NULL || buffer[0] == '\n') {
-        return NULL;
+        return NULL; // Return NULL for empty input
     }
     buffer[strcspn(buffer, "\n")] = 0; // Remove newline character
     struct tree* node = calloc(1, sizeof(struct tree));