diff --git a/AirFighter/FormMapWithSetAircrafts.cs b/AirFighter/FormMapWithSetAircrafts.cs
index b7228a9..f1894db 100644
--- a/AirFighter/FormMapWithSetAircrafts.cs
+++ b/AirFighter/FormMapWithSetAircrafts.cs
@@ -44,7 +44,6 @@ namespace AirFighter
                     }
                     break;
 
-
             }
             if (map != null)
             {
@@ -66,7 +65,7 @@ namespace AirFighter
             if (form.ShowDialog() == DialogResult.OK)
             {
                 DrawingObjectAircraft aircraft = new(form.SelectedAircraft);
-                if (_mapAircraftsCollectionGeneric + aircraft)
+                if (_mapAircraftsCollectionGeneric + aircraft != -1)
                 {
                     MessageBox.Show("Object is added");
                     pictureBox.Image = _mapAircraftsCollectionGeneric.ShowSet();
@@ -89,7 +88,7 @@ namespace AirFighter
                 return;
             }
             int pos = Convert.ToInt32(maskedTextBoxPostion.Text);
-            if (_mapAircraftsCollectionGeneric - pos)
+            if (_mapAircraftsCollectionGeneric - pos != null)
             {
                 MessageBox.Show("Object is deleted");
                 pictureBox.Image = _mapAircraftsCollectionGeneric.ShowSet();