diff --git a/day_04/1.rb b/day_04/1.rb
index 4ff3e6b..2403679 100755
--- a/day_04/1.rb
+++ b/day_04/1.rb
@@ -13,8 +13,8 @@ class Main
     @sum = 0
 
     grid = Grid.new(data)
-    (0...grid.rows.size).each do |row_index|
-      (0...grid.columns.size).each do |column_index|
+    (0...grid.size).each do |row_index|
+      (0...grid[row_index].size).each do |column_index|
         cell = grid.cell_at(row_index, column_index)
         next unless cell.value == "@"