题解 | #字符串排序#

s = input()
s = list(s)
len_s = len(s)
i = 0
while i < len_s:
    if 'a'<= s[i]<= 'z' or 'A'<= s[i] <= 'Z' : 
        t = i
        j = i+1
        while j < len_s:
            if 'a'<= s[j]<= 'z' or 'A'<= s[j] <= 'Z' :
                if s[t].upper() > s[j].upper():
                    s[t],s[j] = s[j],s[t]
                t = j
            j += 1
        len_s  -= 1
        i = -1
    i += 1      
print(''.join(s))