diff --git a/src/main/java/org/jugbd/marathon/day2/BiggestNumber.java b/src/main/java/org/jugbd/marathon/day2/BiggestNumber.java
index 2b1ccf1..cac8caf 100644
--- a/src/main/java/org/jugbd/marathon/day2/BiggestNumber.java
+++ b/src/main/java/org/jugbd/marathon/day2/BiggestNumber.java
@@ -8,7 +8,7 @@ public static long findTheNextBiggerNumber(long n) {
         int ar[] = new int[20]; // long is 64 bit, so max 19 digits can be possible
         int length = 0, tmp;
         boolean found = false;
-        while (n > 0) {
+        while (n != 0) {
 
             ar[length++] = (int) (n % 10);
             n /= 10;
diff --git a/src/test/java/org/jugbd/marathon/day2/BiggestNumberTest.java b/src/test/java/org/jugbd/marathon/day2/BiggestNumberTest.java
index e11dd53..a5e3f40 100644
--- a/src/test/java/org/jugbd/marathon/day2/BiggestNumberTest.java
+++ b/src/test/java/org/jugbd/marathon/day2/BiggestNumberTest.java
@@ -16,6 +16,7 @@ public void basicTests() {
         assertEquals(414, BiggestNumber.findTheNextBiggerNumber(144));
         assertEquals(-1, BiggestNumber.findTheNextBiggerNumber(111));
         assertEquals(-1, BiggestNumber.findTheNextBiggerNumber(531));
-        assertEquals(753772, BiggestNumber.findTheNextBiggerNumber(737752));
+        assertEquals(752377, BiggestNumber.findTheNextBiggerNumber(737752));
+        assertEquals(-213, BiggestNumber.findTheNextBiggerNumber(-231));
     }
-}
\ No newline at end of file
+}