In a certain code, 'MIGHTY' is written as 'BJFISN'. How is 'BUILDER'…

1  2    3    4   5    6   7     8    9  10  11  12  13

 A   B   C    D   E    F   G    H    I    J    K    L   M

 ↓    ↓    ↓    ↓    ↓     ↓   ↓    ↓     ↓   ↓    ↓    ↓    ↓

 Z   Y    X   W   V    U   T    S    R   Q   P    O   N

26  25  24  23  22  21  20  19  18  17  16  15  14

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THE LOGIC FOLLOWED HERE IS :

MAKE THE WORD LIKE THAT

MIGHTY = YIGHTM

Y → (OPPOSITE) → B

I → (+1) → J

G → (-1 ) → F

H → (+1) → I

T → (-1 ) → S

M  → (OPPOSITE) → N

SIMILARLY

MAKE THE WORD LIKE THAT

BUILDER = RUILDEB

R → (OPPOSITE) → I

U → (+1) → V

I → (-1 ) → H

L → (+1) → M

D → (-1 ) → C

E → (+1) → F

B → (OPPOSITE ) → Y