python 3 prefix to infix without too many parethesis

[jezkator at gmail.com]

Hi, I have got a problem.
I wrote a code for prefix to infix. It works, but I need improve it
so on input there will be only necessary parentheses. Can u help me?
Here is the code:

import re
a = input()

class Calculator:

    def __init__ (self):
        self.stack = []

    def push (self, p):
        if p in ['+', '-', '*', '/', "**"]:
            op1 = self.stack.pop ()
            op2 = self.stack.pop ()
            self.stack.append ('(%s%s%s)' % (op1, p, op2))

            
            print("op1 =", op1)
            print("op2 =", op2)
            print("p=", p)
            print(self.stack)

        else:
            self.stack.append (p)


    def convert (self, l):
        l.reverse ()
        for e in l:
            self.push (e)
        return self.stack.pop ()

c = Calculator ()

print (c.convert (re.findall(r'\d+|\*\*|[-+*/]', a)))


input is like /-*+*++**85 27 39 87 65 65 37 63 91