using System;

using System.Collections.Generic;

​

public class Program

{

    public static bool isOperand(char symbol){

        if((symbol>='a' && symbol<='z') || 

             (symbol>='A' && symbol<='Z'))

            return true;

        else

        return false;

    }

    public static string getInfix(string s){

        Stack<string> stack = new Stack<string>();

        for(int i=0; i<s.Length; i++)

        {

            if(isOperand(s[i]))

            {

               stack.Push(s[i]+"");

            }else{

                string part1 = stack.Pop();

                string part2 = stack.Pop();

                stack.Push("("+part2+s[i]+part1+")");

            }

        }

        return stack.Pop();

    }

    public static void Main(String []args) 

    { 

        String exp = "ab*c+"; 

        Console.WriteLine( getInfix(exp)); 

    } 

}