diff --git a/solutions/037.md b/solutions/037.md
index d77e21d..2b2545a 100644
--- a/solutions/037.md
+++ b/solutions/037.md
@@ -128,4 +128,28 @@ class Solution:
         return count
 ```
 
+### O(nm) solution using regular expressions
+
+We will check every word that inside has any character that not allowed
+
+#### PHP
+class Solution {
+
+    /**
+     * @param String $allowed
+     * @param String[] $words
+     * @return Integer
+     */
+    function countConsistentStrings($allowed, $words) {
+        $result = 0;
+        foreach($words as $word)
+        {
+            if(!preg_match('/[^' . $allowed . ']/', $word)){
+                $result++;
+            }
+        }
+        return $result;
+    }
+}
+
 ***NB***: If you want to get community points please suggest solutions in other languages as merge requests.