1078 字符串压缩与解压 （20 分） python

str1 = input()
ipt = list(input())
new_list = []
if str1 == "C":
    a = ipt[0]
    ipt.append("0")
    count = 1
    for i in ipt[1:]:
        if i == a:
            count += 1
        else:
            if count != 1:
                new_list.append(str(count))
                new_list.append(a)
                count = 1
            else:
                new_list.append(a)
            a = i
    print("".join(new_list))
b = ""
res_str = ""
if str1=="D":
    for i in range(len(ipt)):
        if ipt[i].isdigit():
            b = b+ipt[i]
        else:
            if b == "":
                res_str += ipt[i]
            else:
                res_str += int(b)*ipt[i]
            b = ""
    print(res_str)