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: Time Limit Exceeded)


n = gets.chomp.split("")
a = n.size
arr = []
a.times do |i|
    if n[i] == "?"
        arr << i
    end
end
ar = arr.size
all = 0
saisyuu = []
["P","D"].repeated_permutation(ar) do |ii|
    count = 0
    souko = []
    # (0..ar-1).each do |j|
    #     n[ar[j]] = (ii[j])

    # end
    (0..a-1).each do |iii|
        if n[iii] == "P" ||  n[iii] == "D"
            
            souko << n[iii]
        else
            souko << ii.shift
        end
    end
    kirei = souko.join
    a = kirei.count("PD")
    b = kirei.count("D")
    if all < a + b
       saisyuu << kirei 
    end

    all = a + b
end
puts saisyuu.pop