Problem:
Score : 200 points

Problem Statement

For a string S consisting of the uppercase English letters P and D, let the doctoral and postdoctoral quotient of S be the total number of occurrences of D and PD in S as contiguous substrings. For example, if S = PPDDP, it contains two occurrences of D and one occurrence of PD as contiguous substrings, so the doctoral and postdoctoral quotient of S is 3.

We have a string T consisting of P, D, and ?.

Among the strings that can be obtained by replacing each ? in T with P or D, find one with the maximum possible doctoral and postdoctoral quotient.

Constraints

1 \leq |T| \leq 2 \times 10^5

T consists of P, D, and ?.

Input

Input is given from Standard Input in the following format:

T

Output

Print one string with the maximum possible doctoral and postdoctoral quotient among the strings that can be obtained by replacing each ? in T with P or D.
If there are multiple such strings, you may print any of them.

Sample Input 1

PD?D??P

Sample Output 1

PDPDPDP

This string contains three occurrences of D and three occurrences of PD as contiguous substrings, so its doctoral and postdoctoral quotient is 6, which is the maximum doctoral and postdoctoral quotient of a string obtained by replacing each ? in T with P or D.

Sample Input 2

P?P?

Sample Output 2

PDPD

Solution in C# (.NET Core 3.1.201) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

    class QuestionB
    {
        public static void Main(string[] args)
        {
            var sw = new System.IO.StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
            Console.SetOut(sw);

            // 文字列の入力
            string s = Console.ReadLine();
            var arr = s.ToCharArray();
            for(var i=0; i<arr.Length; i++)
            {
                if (arr[i] == '?')
                {
                    if (i > 0 && arr[i - 1] == 'P')
                        arr[i] = 'D';
                    else if (i < arr.Length - 1 && arr[i + 1] == 'P')
                        arr[i] = 'D';
                    else if (i < arr.Length - 1 && arr[i + 1] == 'D')
                        arr[i] = 'P';
                    else if (i < arr.Length - 1 && arr[i + 1] == '?')
                        arr[i] = 'P';
                }
            }

            string result = string.Join("", arr);

            Console.WriteLine(result);

            Console.Out.Flush();
        }
    }