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 Go (1.14.1) (judge verdict: Accepted)

package main

import (
	"bufio"
	"fmt"
	"math"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)

func nextInt() int {
	sc.Scan()
	num, err := strconv.Atoi(sc.Text())
	if err != nil {
		panic(err)
	}
	return num
}

func nextString() string {
	sc.Scan()
	return sc.Text()
}

func getMin(x ...int) int {
	min := math.MaxInt64
	for i := 0; i < len(x); i++ {
		if x[i] < min {
			min = x[i]
		}
	}
	return min
}

func pow(x, pow int) int {
	ans := x
	for i := 1; i < pow; i++ {
		ans = ans * x
	}
	return ans
}

func abs(x int) int {
	if x < 0 {
		return -x
	}
	return x
}

var rdr = bufio.NewReaderSize(os.Stdin, 10000000)

func readLine() string {
	buf := make([]byte, 0, 10000000)
	for {
		l, p, err := rdr.ReadLine()
		if err != nil {
			panic(err)
		}
		buf = append(buf, l...)
		if !p {
			break
		}
	}
	return string(buf)
}

func main() {

	t := readLine()
	w := bufio.NewWriter(os.Stdout)
	defer w.Flush()

	for i := 0; i < len(t); i++ {
		if t[i] == '?' {
			fmt.Fprint(w, "D")
		} else {
			fmt.Fprintf(w, "%c", t[i])
		}
	}
	fmt.Fprintln(w, "")
}