diff --git a/String/KeyboardRow.swift b/String/KeyboardRow.swift
index 5de42c82..8e81fa3c 100644
--- a/String/KeyboardRow.swift
+++ b/String/KeyboardRow.swift
@@ -1,7 +1,7 @@
 /**
  * Question Link: https://leetcode.com/problems/keyboard-row/
  * Primary idea: Use filter to determine the word is subset or not.
- * 
+ *
  * Note: You can also use intersect() or union() functions to solve this problem.
  *
  * Time Complexity: O(nm), Space Complexity: O(n)
@@ -9,15 +9,15 @@
  */
 
 class KeyboardRow {
-    func findWords(_ words: [String]) -> [String] {
-        let rowOne = "qwertyuiop", rowTwo = "asdfghjkl", rowThree = "zxcvbnm"
+  func findWords(_ words: [String]) -> [String] {
+      let rowOne = "qwertyuiop", rowTwo = "asdfghjkl", rowThree = "zxcvbnm"
 
-        return words.filter { word in rowOne.contains(word) || rowTwo.contains(word) || rowThree.contains(word) }
-    }
+      return words.filter { word in rowOne.contains(word.lowercased()) || rowTwo.contains(word.lowercased()) || rowThree.contains(word.lowercased()) }
+  }
+}
 
-    extension String {
-        func contains(_ word: String) -> Bool {
-            return word.filter { c in !self.contains(c) }.characters.count == 0
-        }
+extension String {
+    func contains(_ word: String) -> Bool {
+        return word.filter { c in !self.contains(c) }.count == 0
     }
-}
\ No newline at end of file
+}