import string

abc = string.ascii_lowercase

C = eval(input())

print((abc[abc.index(C) + 1]))

import string

ab = string.ascii_lowercase

bc = ab[1:] + 'a'

c = eval(input())

for a, b in zip(ab, bc):

    if a == c:

        print(b)

import string

abc = string.ascii_lowercase
C = eval(input())
print((abc[abc.index(C) + 1]))

import string

ab = string.ascii_lowercase
bc = ab[1:] + "a"
c = eval(input())
for a, b in zip(ab, bc):
    if a == c:
        print(b)

-abc = string.ascii_lowercase -C = eval(input()) -print((abc[abc.index(C) + 1])) +ab = string.ascii_lowercase +bc = ab[1:] + "a" +c = eval(input()) +for a, b in zip(ab, bc): +    if a == c: +        print(b)