HTUU
      +---------
PTPQG | LPPNHJFL
       -PTPQG
        =====
        HTUFNJ
       -HLLTHF
        ======
         PTPGYF
        -PYNTTT
         ======
          PGQFPL
         -PYNTTT
          ======
           PPHTQ

base: 11
letters: FGHJLNPQTUY
difficulty: hard
restrictions: no multiplication