diff --git a/README.md b/README.md
index 834ba621..5ce9f592 100644
--- a/README.md
+++ b/README.md
@@ -689,6 +689,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 1381. Design a Stack With Increment Operation                                       | [Link](https://leetcode.com/problems/design-a-stack-with-increment-operation/)                                       | [Link](./lib/medium/1381_design_a_stack_with_increment_operation.rb)                                       | [Link](./test/medium/test_1381_design_a_stack_with_increment_operation.rb)                                       |
 | 1382. Balance a Binary Search Tree                                                  | [Link](https://leetcode.com/problems/balance-a-binary-search-tree/)                                                  | [Link](./lib/medium/1382_balance_a_binary_search_tree.rb)                                                  | [Link](./test/medium/test_1382_balance_a_binary_search_tree.rb)                                                  |
 | 1387. Sort Integers by The Power Value                                              | [Link](https://leetcode.com/problems/sort-integers-by-the-power-value/)                                              | [Link](./lib/medium/1387_sort_integers_by_the_power_value.rb)                                              | [Link](./test/medium/test_1387_sort_integers_by_the_power_value.rb)                                              |
+| 1395. Count Number of Teams                                                         | [Link](https://leetcode.com/problems/count-number-of-teams/)                                                         | [Link](./lib/medium/1395_count_number_of_teams.rb)                                                         | [Link](./test/medium/test_1395_count_number_of_teams.rb)                                                         |
 | 1400. Construct K Palindrome Strings                                                | [Link](https://leetcode.com/problems/construct-k-palindrome-strings/)                                                | [Link](./lib/medium/1400_construct_k_palindrome_strings.rb)                                                | [Link](./test/medium/test_1400_construct_k_palindrome_strings.rb)                                                |
 | 2116. Check if a Parentheses String Can Be Valid                                    | [Link](https://leetcode.com/problems/check-if-a-parentheses-string-can-be-valid/)                                    | [Link](./lib/medium/2116_check_if_a_parentheses_string_can_be_valid.rb)                                    | [Link](./test/medium/test_2116_check_if_a_parentheses_string_can_be_valid.rb)                                    |
 | 2425. Bitwise XOR of All Pairings                                                   | [Link](https://leetcode.com/problems/bitwise-xor-of-all-pairings/)                                                   | [Link](./lib/medium/2425_bitwise_xor_of_all_pairings.rb)                                                   | [Link](./test/medium/test_2425_bitwise_xor_of_all_pairings.rb)                                                   |
diff --git a/leetcode-ruby.gemspec b/leetcode-ruby.gemspec
index cbcd8a2c..d8affb58 100644
--- a/leetcode-ruby.gemspec
+++ b/leetcode-ruby.gemspec
@@ -5,7 +5,7 @@ require 'English'
 ::Gem::Specification.new do |s|
   s.required_ruby_version = '>= 3.0'
   s.name = 'leetcode-ruby'
-  s.version = '8.5.6'
+  s.version = '8.5.7'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'
diff --git a/lib/medium/1395_count_number_of_teams.rb b/lib/medium/1395_count_number_of_teams.rb
new file mode 100644
index 00000000..fb80c764
--- /dev/null
+++ b/lib/medium/1395_count_number_of_teams.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/count-number-of-teams/
+# @param {Integer[]} rating
+# @return {Integer}
+def num_teams(rating)
+  size = rating.size
+  up = ::Array.new(size, 0)
+  down = ::Array.new(size, 0)
+  result = 0
+
+  (0...size).each do |i|
+    i.downto(0) do |j|
+      if rating[i] > rating[j]
+        up[i] += 1
+        result += up[j]
+      end
+    end
+  end
+
+  (0...size).each do |i|
+    i.downto(0) do |j|
+      if rating[i] < rating[j]
+        down[i] += 1
+        result += down[j]
+      end
+    end
+  end
+
+  result
+end
diff --git a/test/medium/test_1395_count_number_of_teams.rb b/test/medium/test_1395_count_number_of_teams.rb
new file mode 100644
index 00000000..96df8569
--- /dev/null
+++ b/test/medium/test_1395_count_number_of_teams.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/1395_count_number_of_teams'
+require 'minitest/autorun'
+
+class CountNumberOfTeamsTest < ::Minitest::Test
+  def test_default_one = assert_equal(3, num_teams([2, 5, 3, 4, 1]))
+
+  def test_default_two = assert_equal(0, num_teams([2, 1, 3]))
+
+  def test_default_three = assert_equal(4, num_teams([1, 2, 3, 4]))
+end