题解 | #字符串排序#

def fun(x):
    return x.lower()

in_str = input()
in_list = list(in_str)
a = [ x for x in range(ord('a'), ord('z') +1)]
A = [ x for x in range(ord('A'), ord('Z') +1)]
tem = []
for i in range(len(in_list)):
    if ord(in_list[i]) in a or ord(in_list[i]) in A: 
        tem.append(in_list[i])
        in_list[i] = 'a'
tem.sort(key=lambda x:fun(x))
flag = 0
for i in range(len(in_list)):
    if in_list[i] == 'a' and flag < len(tem):
        in_list[i] = tem[flag]
        flag += 1
print(''.join(in_list))