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 Ruby (2.7.1) (judge verdict: Wrong Answer)

t = gets.chomp.split('')

if t[0] == '?' and t.length == 1
  t[0] = 'D'
end

if t[0] == '?' and t.length > 1
  if t[1] == 'D'
    t[0] = 'P'
  elsif t[1] == '?'
    t[0] = 'P'
    t[1] = 'D'
  else
    t[0] = 'D'
  end
end

0.upto t.length-1 do |i|
  if t[i] == '?' and t[i+1] == '?'
    if t[i-1] == 'P'
      if t[i+2] == 'D'
        t[i] = 'D'
        t[i+1] = 'P'
      else
        t[i] = 'D'
        t[i+1] = 'D'
      end
    end
  else
    if t[i] == '?'
      if t[i-1] == 'P'
        t[i] = 'D'
      elsif t[i+1] == 'D'
        t[i] = 'P'
      else
        t[i] = 'D'
      end
    end
  end
end

puts t.join('')