In a certain code, BELIEF is written as AFKJDG. How is SELDOM written in that code language?

In a certain code, BELIEF is written as AFKJDG. How is SELDOM written in that code language?

Explanation

B - 1 = A

E + 1 = F

L - 1 = K

I + 1 = J

E - 1 = D

F + 1 = G

BELIEF = AFKJDG


S - 1 = R

E + 1 = F

L - 1 = K

D + 1 = E

O - 1 = N

M + 1 = N

SELDOM = RFKENN