diff --git a/src/input.handler.ts b/src/input.handler.ts
index fbdbf32..4e112b5 100644
--- a/src/input.handler.ts
+++ b/src/input.handler.ts
@@ -79,6 +79,7 @@ export class InputHandler {
 
         switch (keyCode) {
             case undefined:
+            case 13:
                 return;
             case 43:
                 this.inputService.changeToPositive();