new_contents: arr = [1, 6, 3, 5, 9, 7]
  
  ans = [1]
  
  for i in range(1, len(arr)):
      t = []
      for j in range(i):
          if arr[i] > arr[j]:
              t.append(ans[j]+1)
          else:
              t.append(ans[j])
  
      ans.append(max(t))
  
  print max(ans)
  
subject: Add longest increasing subsequence