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# (Mono-csc 3.5.0) (judge verdict: Runtime Error)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using static System.Console;
using static System.Math;
using static System.Array;

class Program
{
    public static void Main()
    {
        var s = ReadLine();
        char[] c = s.ToCharArray();
        if(IndexOf(c, 'P') == IndexOf(c, 'D'))
        {
            for(int i = 0; i < c.Length; i++)
            {
                if(i % 2 == 0)
                {
                    c[i] = 'P';
                }
                else
                {
                    c[i] = 'D';
                }
            }
        }
        else
        {
            if(IndexOf(c, '?') == 0)
            {
                for(int i = Min(s.IndexOf('P'), s.IndexOf('D')); 0 <= i; i--)
                {
                    c[i] = c[i + 1] == 'P' ? 'D' : 'P';
                }
            }
            for(int i = IndexOf(c, '?'); i < c.Length; i++)
            {
                if(s[i] == '?')
                {
                    c[i] = c[i - 1] == 'P' ? 'D' : 'P';
                }
            }
        }
        WriteLine(new string(c));
    }
}