class Solution:
    def Typing(self , s :str):
        if str=='':
            return ''
        if str is None:
            return ''
        # write code here
        length=len(s)
        data=list(s)
        res=[]
        for i in range(length):
            if i==0 and data[i]=='<':
                data[0]=-1
            elif data[i]=='<':
                for j in reversed(range(0,i)):
                    if data[j]!=-1 and j!=-1:
                        data[j]=-1
                        break
                data[i]=-1 # 当前字符的 实际的前面一个 字符无用
        for elem in data:
            if elem != -1:
                res.append(elem)
        return ''.join(res)