????????
      +---------
GQTXT | VXLTJTNY
       -GQTXT
        =====
        PYQNUT
       -PXHNRN
        ======
         ZQHGJN
        -ZLHWGQ
         ======
          LMXGUY
         -JHJXGX
          ======
          ?????G

base: 16
letters: GHJLMNPQRTUVWXYZ
difficulty: hard