def zenslis(lis):
    ops = '()*/+-';s='';lis2 = []
    for i in lis:
        if '0' <= i <= '9':
            s += i
            num = True
        elif i in ops:
            if num == True:
                lis2.append(s)
                s=''
                num = False
            lis2.append(i)
    if s:
        lis2.append(s)
    return lis2

def intpost(expr):
    ops = {'(':0,')':0,'**':1,'*':2,'/':2,'+':3,'-':3}
    stack = []
    post = []
    for z in expr:
        if z not in ops:
            post.append(z)
        else:
            if z != ')' and (not stack or z == '(' or stack[-1] == '(' or ops[z] < ops[stack[-1]]):
                stack.append(z)
            elif z == ')':
                while True:
                    x = stack.pop()
                    if x != '(':
                        post.append(x)
                    else:
                        break
            else:
                while True:
                    if stack and stack[-1] != '(' and ops[z] >= ops[stack[-1]]:
                        post.append(stack.pop())
                    else:
                        stack.append(z)
                        break
        #print(stack)
    while stack:
        post.append(stack.pop())
    return post

运行代码

if __name__ == '__main__':
    s = input()
    lis = zenslis(s)
    post = intpost(lis)
    print(' '.join(post))