import sys

x = str(input())

is_right = True
for i in x:
    if ord(i) >= 97 and ord(i) <= 122:
        pass
    else:
        is_right = False

if is_right == True:
    print(x[::-1])
else:
    pass

【目的】

小写字母的ASCII码范围为:97~122(97+26-1=122)

ASCII码表:https://www.asciim.cn/