n = int(input())
m = []
if n > 0:
    n = str(n)
    print(int(n[::-1]))
else:
    for i in str(n):
        m.append(i)
    m.pop(0) # 删除负号
    for i in m[::-1]:
        if i == '0':
            m.pop() # 删除‘0’
    print(int(''.join(map(str, m)))*-1)