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 Rust (1.42.0) (judge verdict: Accepted)

#[allow(dead_code)]
fn main() {
    let t = i::s();
    for c in t {
        print!("{}", if c == '?' { 'D' } else { c });
    }
    println!();
}

#[allow(unused_imports)]
use std::cmp::*;
#[allow(unused_imports)]
use std::collections::{HashMap, HashSet, VecDeque};
#[allow(unused_imports)]
use std::io::*;
#[allow(unused_imports)]
use std::num::*;
#[allow(unused_imports)]
use std::str::*;

#[allow(dead_code)]
mod i {
    use super::*;

    pub fn read<T: FromStr>() -> T {
        stdin()
            .bytes()
            .map(|c| c.unwrap() as char)
            .skip_while(|c| c.is_whitespace())
            .take_while(|c| !c.is_whitespace())
            .collect::<String>()
            .parse::<T>()
            .ok()
            .unwrap()
    }
    pub fn str() -> String {
        read()
    }
    pub fn s() -> Vec<char> {
        str().chars().collect()
    }
    pub fn i() -> i64 {
        read()
    }
    pub fn u() -> usize {
        read()
    }
    pub fn u2() -> (usize, usize) {
        (read(), read())
    }
    pub fn u3() -> (usize, usize, usize) {
        (read(), read(), read())
    }
    pub fn u4() -> (usize, usize, usize, usize) {
        (read(), read(), read(), read())
    }
    pub fn u5() -> (usize, usize, usize, usize, usize) {
        (read(), read(), read(), read(), read())
    }
    pub fn u6() -> (usize, usize, usize, usize, usize, usize) {
        (read(), read(), read(), read(), read(), read())
    }
    pub fn f() -> f64 {
        read()
    }
    pub fn c() -> char {
        read::<String>().pop().unwrap()
    }
    pub fn iv(n: usize) -> Vec<i64> {
        (0..n).map(|_| i()).collect()
    }
    pub fn iv2(n: usize) -> Vec<(i64, i64)> {
        (0..n).map(|_| iv(2)).map(|a| (a[0], a[1])).collect()
    }
    pub fn iv3(n: usize) -> Vec<(i64, i64, i64)> {
        (0..n).map(|_| iv(3)).map(|a| (a[0], a[1], a[2])).collect()
    }
    pub fn uv(n: usize) -> Vec<usize> {
        (0..n).map(|_| u()).collect()
    }
    pub fn uv2(n: usize) -> Vec<(usize, usize)> {
        (0..n).map(|_| uv(2)).map(|a| (a[0], a[1])).collect()
    }
    pub fn uv3(n: usize) -> Vec<(usize, usize, usize)> {
        (0..n).map(|_| uv(3)).map(|a| (a[0], a[1], a[2])).collect()
    }
    pub fn uv4(n: usize) -> Vec<(usize, usize, usize, usize)> {
        (0..n)
            .map(|_| uv(4))
            .map(|a| (a[0], a[1], a[2], a[3]))
            .collect()
    }
    pub fn fv(n: usize) -> Vec<f64> {
        (0..n).map(|_| f()).collect()
    }
    pub fn cmap(h: usize) -> Vec<Vec<char>> {
        (0..h).map(|_| s()).collect()
    }
}