????????
      +---------
UTJRF | NFYWQYNJ
       -UTJRF
        =====
        JJFWFY
       -XYTQWH
        ======
         UJFYQN
        -TYRNFE
         ======
          TNXFXJ
         -TENTFR
          ======
          ??????

base: 13
letters: EFHJNPQRTUWXY
difficulty: medium
missing: P