????????
      ----------
GQYQU ) YMXRRPNX
       -GQYQU
        =====
         RHUQP
        -NQLQP
         =====
         MMULLN
        -MLTWLR
         ======
           UHTTX
          -QXUXT
           =====
           ?????

base: 13
symbols: GHLMNPQRTUWXY
difficulty: medium