??????
    --------
FWA ) WWPLLX
     -JWL
      ===
       LLL
      -LFP
       ===
        PFL
       -NRW
        ===
         WJX
        -JWL
         ===
         ???

base: 10
symbols: AFJLNPRUWX
difficulty: medium
hints: F << X
missing: U