def func(x):
p = 0
i = 0
string = "qwertyuiopasdfghjklzxcvbnm"
if(x != "m"):
while(i < len(string)):
if(string[i] == x):
p = i
i += 1
print(string[p + 1])
else:
print("q")
x = input()
func(x)
ZGVmIGZ1bmMoeCk6CglwID0gMAoJaSA9IDAKCXN0cmluZyA9ICJxd2VydHl1aW9wYXNkZmdoamtsenhjdmJubSIKCWlmKHggIT0gIm0iKToKCQl3aGlsZShpIDwgbGVuKHN0cmluZykpOgoJCQlpZihzdHJpbmdbaV0gPT0geCk6CgkJCQlwID0gaQoJCQlpICs9IDEKCQlwcmludChzdHJpbmdbcCArIDFdKQkKCWVsc2U6CgkJcHJpbnQoInEiKQp4ID0gaW5wdXQoKQkKZnVuYyh4KQk=