????????
      +---------
YYMXJ | QHNTMJYR
       -NNXJH
        =====
        TQQQGJ
       -TJWQYN
        ======
          RLHTY
         -FPJHT
          =====
          HHJHHR
         -HHHPFW
          ======
          ??????

base: 15
letters: FGHJLMNPQRTUWXY
difficulty: hard
missing: U