def l_conv(l1,n):
    alphabet = list("ABCDEFGHIJKLMNOPQRSTUVWXYZ")
    p1 = alphabet.index(l1)
    if (p1 - n%26) >=  0 :
         p2 = p1 -n%26
    else:
         p2 = p1 -n%26 +26
    l2 = alphabet[p2]
    return l2

s = input()
t = ""
s_len = len(s)

for i in range(s_len):
    t = t + l_conv(s[i],i+1)    

print (t)