              2,p
          _.-'   `-----.....______               3,s
         0                        5          _.-'   `---...___
        / \                 __..-' \        0                 5
       []  [2]             4,r      [] =>  / \          __..-' \
                     __..-'   \           []  [3]      4,r      []
                    3,s        [5]                   _'   \
                  _'   \                            [3]    [5]
                 [2]    [4]
 
