XUNX
      +---------
WJMYW | RNJMWXWR
       -YYNMU
        =====
        MYMRNX
       -MUUMEE
        ======
         MHFXMW
        -MGFRHM
         ======
           RXUMR
          -YYNMU
           =====
           MNMTX

base: 13
letters: EFGHJMNRTUWXY
difficulty: medium
missing: T