#-*-coding:utf-8-*-

def trim(s):

    if s[0]==' ':

        return s[1:]

    elif s[-1]==' ':

        return s[:-1]

    elif s[0]==' ' and s[-1]==' ':

        return s[1:-1]         

    else:

        return s

s=input('请输入:')

print(trim(s))

input()