diff --git a/labs/lab4/main.js b/labs/lab4/main.js
index 6dd09ad..fc681a3 100644
--- a/labs/lab4/main.js
+++ b/labs/lab4/main.js
@@ -18,7 +18,7 @@ function main(formName) {
 }
 
 function checkParity(n) { 
-    return n % 2 == getSumOfDigits(n) % 2;
+    return Math.abs(n % 2) == getSumOfDigits(n) % 2;
 }
 
 function isNotNumber(val) {