In certain code language, 'STYLE' is written as '181924114'. How would 'FIRST' be written in the same code language.

58171819

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

***********************************************

THE LOGIC FOLLOWED HERE IS:

THE NUMERICAL VALUE OF EACH LETTER GET DECREASED BY 1 TO GET THE CODE

S → 19 → 19 - 1 = 18

T → 20 → 20 - 1 = 19

Y → 25  → 25 - 1 = 24

L → 12 → 12 - 1 = 11

E → 5 → 5 - 1 = 4

SIMILARLY

F → 6 → 6 - 1 = 5

I → 9 → 9 - 1 = 8

R → 18  → 18 - 1 = 17

S → 19 → 19 - 1 = 18

T → 20 → 20 - 1 = 19

SO THE CODE IS  58171819