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 Kotlin (1.3.71) (judge verdict: Time Limit Exceeded)

/** B */
fun main(args: Array<String>) {

    var t = readLine()!!

    /* TLE
    // 評価パターンをリスト化
    var evalTargetStrings = mutableListOf<String>()
    evalTargetStrings.add(t)
    for (i in t.indices) {
        if (t[i] == '?') {
            evalTargetStrings = getEvalStrings(evalTargetStrings, i)
        }
    }

    // 指数の算出
    var score = 0
    var outputString = t
    for (evalTargetString in evalTargetStrings) {
        val tempScore = evalScore(evalTargetString)
        if (score < tempScore) {
            score = tempScore
            outputString = evalTargetString
        }
    }
     */

    var score = 0
    var evalTargetString = t

    // 評価パターンをリスト化
    var evalTargetStrings = mutableListOf<String>()
    evalTargetStrings.add(t)
    for (i in t.indices) {
        if (t[i] == '?') {
            val evalTargetStringsNew = getEvalStrings(evalTargetStrings, i)

            for (evalTargetStringNew in evalTargetStringsNew) {
                val tempScore = evalScore(evalTargetStringNew)
                if (score < tempScore) {
                    score = tempScore
                    evalTargetString = evalTargetStringNew
                    evalTargetStrings = mutableListOf(evalTargetString)
                }
            }
        }
    }

    println(evalTargetString)
}

private fun getEvalStrings(evalTargetStrings: MutableList<String>, i: Int): MutableList<String> {
    val evalStringsNew = mutableListOf<String>()
    for (evalTargetString in evalTargetStrings) {
        val tempT1 = evalTargetString.replaceRange(i, i + 1, "P")
        val tempT2 = evalTargetString.replaceRange(i, i + 1, "D")
        evalStringsNew.add(tempT1)
        evalStringsNew.add(tempT2)
    }
    return evalStringsNew
}

private fun evalScore(s: String): Int {
    var score = 0
    var beforeChar = 'X'
    for (i in s.indices) {
        if (s[i] == 'D') {
            score++
            if (beforeChar == 'P') {
                score++
            }
        }
        beforeChar = s[i]
    }

    return score
}