????????
      +---------
NGTEE | HRNYYEEN
       -NGTEE
        =====
         RXUUE
        -NGTEE
         =====
         UXEGFE
        -UYGYGG
         ======
          EWLFWN
         -EFGWEU
          ======
          ??????

base: 13
letters: EFGHLNPRTUWXY
missing: P
difficulty: medium