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 Perl (5.26.1) (judge verdict: Accepted)

use strict;
use warnings;
use feature 'say';
use Data::Dumper;

chomp(my $str = <STDIN>);

my @rep = qw(P D);
my $max_index_cnt = 0;
my $target_str = '';
for my $rep (@rep) {
  my $target = '';
  ($target = $str) =~ s/\?/$rep/g;

  my $before = length($target);
  my $total_pd_cnt = 0;
  for my $rep ( qw/ D PD / ) {

    my $occurrence_cnt = (() = $target =~ m/$rep/g);
    $total_pd_cnt += $occurrence_cnt;
  }

  if( $total_pd_cnt > $max_index_cnt) {
    $max_index_cnt = $total_pd_cnt;
    $target_str = $target;
  }
}
print $target_str,"\n";