diff --git a/a1/program.c b/a1/program.c
index 4169d13..531c295 100644
--- a/a1/program.c
+++ b/a1/program.c
@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <math.h>
+#include <string.h>
 
 #define MAX_LINE_LENGTH 100
 
@@ -8,6 +9,11 @@ int main() {
   char uloha[MAX_LINE_LENGTH];
 
   while (fgets(uloha, MAX_LINE_LENGTH, stdin) != NULL) {
+    if (strlen(uloha) <= 1) {
+      printf("OK\n");
+      continue;
+    }
+
     int cislo1, cislo2, vysledok_zadany;
     char operacia;
 
@@ -48,4 +54,4 @@ int main() {
   }
 
   return 0;
-}
+}
\ No newline at end of file