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: Accepted)

while line = gets
    next if line.to_s.strip == ""
    left_char = ""
    right_char = ""
    line.strip!
    length = line.size
    line.size.times do |i|
        current_char = line[i]
        if current_char == "?"
            if i == (length - 1)
                right_char = ""
            else
                right_char = line[i + 1]
            end
            if left_char == "P"
                # 左がPの場合はDにする
                line[i] = "D"
            else
                # 左がDの場合
                if right_char == ""
                    # 最後の文字ならDにする
                    line[i] = "D"
                elsif right_char == "?"
                    # 次が?の場合はPにする
                    line[i] = "P"
                elsif right_char == "D"
                    # 次がDの場合はPにする
                    line[i] = "P"
                else
                    # それ以外はDにする
                    line[i] = "D"
                end
            end
        end
        left_char = line[i]
    end
    puts line
end