????????
      +---------
UMETT | LFXMUWLE
       -TXWJJ
        =====
        QUFXXW
       -QGFUYE
        ======
         UGTXEL
        -QYMXJL
         ======
          QQGMGE
         -QGFUYE
          ======
          ??????

base: 13
letters: EFGJLMQRTUWXY
difficulty: medium
missing: R