"""a = input("数：")
num = int(a)
if num % 2 == 0:
    print(num * 2)
else:
    print(num + 1)

while num >= 2:
    num /= 2
print(num)

sb = range(114,514)
for i in sb :
    print(i)"""

"""
a =input("")
b= ''
for i in a:
    b = i + b#从右边倒着加字符
print(b)
"""
# for i in 0,3 为什么i会输出1和3
"""
str = '123'
print(str[3])为什么会超范围
"""
#此处开始
str = input("")
length = len(str)
num = 0
shot = ""
for i in range(0, length):
    num = length - i - 1
    shot += str[num]
print(shot)