# Message decipher

Computer Science Level 3

At your communication center, you intercept a message transmit by your ennemy. This message is : FKHHCGCXHD. Also, one of spy (hopefully) find the encryption formula used by your ennemy : $$7x + 2\pmod{26}$$. X variable is the rank of the letter in the alphabet (starting at A = 1). What is the sum of all the letters of original message ?

(example for the word "he" the sum is 8 + 5 = 13).

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