diff --git a/Database.cs b/Database.cs
index c490060..67d6796 100644
--- a/Database.cs
+++ b/Database.cs
@@ -12,7 +12,7 @@ namespace MineSweeper
             public int loses { get; set; } = 0;
         }
         private record Root(List<PlayerData> players);
-        private Root root;
+        private readonly Root root;
         public Database()
         {
             path = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "MineSweeper by H1K0");
diff --git a/Field.cs b/Field.cs
index 6237ad2..5d10daa 100644
--- a/Field.cs
+++ b/Field.cs
@@ -19,8 +19,7 @@
                 throw new ArgumentException("The number of mines can not be negative.");
             if (nmines > input_width * input_height)
                 throw new ArgumentException("The number of mines can not be greater than the number of all cells.");
-            width = input_width;
-            height = input_height;
+            (width, height) = (input_width, input_height);
             size = width * height;
             cells = new List<Cell>();
             for (int i = 0; i < size; i++)