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: Accepted)

using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Linq;
using static MyIO;
using System.IO;

namespace atcoder
{
    class Program
    {
        static void Main(string[] args)
        {
            var P = GetString();
            char[] P2 = new char[P.Length];

            for (int i = 0; i < P.Length; i++)
            {
                if (P[i] != '?')
                {
                    P2[i] = P[i];
                }
                else
                {
                    P2[i] = 'D';
                    /*
                    if (i == 0)
                    {
                        if (P[i + 1] == 'P')
                        {
                            P2[i] = 'D';
                        }
                        else
                        {
                            P2[i] = 'P';
                        }
                    }
                    else if (P[i - 1] == 'D')
                    {
                        if (i != P.Length - 1 || P[i + 1] == 'D')
                            P2[i] = 'D';
                    }
                    else
                    {
                        P2[i] = 'D';
                    }
                    */
                }
            }

            Console.WriteLine(P2);



            return;
        }
    }
}

public static class MyIO
{
    private static string[] args = null;
    private static int num = -1;
    private static int used = -1;

    private static string getArg()
    {
        if (used == num)
        {
            args = Console.ReadLine().Split(' ');
            num = args.Length;
            used = 0;
        }
        return args[used++];
    }

    public static int GetInt() => int.Parse(getArg());
    public static long GetLong() => long.Parse(getArg());
    public static double GetDouble() => double.Parse(getArg());
    public static string GetString() => getArg();
    public static char GetChar() => getArg()[0];
    public static int[] GetInts(int N) => Enumerable.Range(0, N).Select(_ => GetInt()).ToArray();
    public static long[] GetLongs(int N) => Enumerable.Range(0, N).Select(_ => GetLong()).ToArray();
    public static double[] GetDoubles(int N) => Enumerable.Range(0, N).Select(_ => GetDouble()).ToArray();
    public static string[] GetStrings(int N) => Enumerable.Range(0, N).Select(_ => GetString()).ToArray();
}