diff --git a/SetArtilleriesGeneric.java b/SetArtilleriesGeneric.java
index 0293a7b..24b4ea1 100644
--- a/SetArtilleriesGeneric.java
+++ b/SetArtilleriesGeneric.java
@@ -20,7 +20,11 @@ public class SetArtilleriesGeneric<T> {
     }
 
     public int insert(T artillery, int position) {
-        if (position < 0 || position > getCount() || getCount() == _maxCount) {
+        if (getCount() == _maxCount) {
+            throw new StorageOverflowException(_maxCount);
+        }
+
+        if (position < 0 || position > getCount()) {
             return -1;
         }
 
@@ -37,6 +41,10 @@ public class SetArtilleriesGeneric<T> {
 
         T result = _places.get(position);
 
+        if (result == null) {
+            throw new ArtilleryNotFoundException(position);
+        }
+
         _places.remove(position);
 
         return result;