????????
      +---------
YWXUR | QWWTNYLY
       -YWXUR
        =====
        MGGXTY
       -MLTEXE
        ======
         MUXMYL
        -MERQPM
         ======
          UHPTWY
         -UHUMNN
          ======
          ??????

base: 14
letters: EGHLMNPQRTUWXY
difficulty: challenging