def construct_ladder(pieces:list[int]):
     ladders = 0

     while len(pieces) > 0:
          currPiece = pieces[0]
          pieces.remove(currPiece)

          if(currPiece == 10):
               ladders += 1
               continue
         
          for piece in pieces:
                    if currPiece + piece == 10:
                         ladders += 1
                         pieces.remove(piece)
                         break
     return ladders

print(construct_ladder([1,9,9,7,0,10,4,4,2,17,1,9,6,6]))