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 Python (3.8.2) (judge verdict: Wrong Answer)

import sys
T = input()


S = ""
j = 0

if T == '?' * len(T):
  S = "PD" * (len(T)//2) + "D" * (len(T)%2)
  print(S)
  sys.exit()

if T[0] == '?':
  j += 1
  while T[j] == '?':
    j += 1
  if T[j] == 'D':
    if j % 2 == 0:
      S += 'DP' * (j//2)
    else:
      S += 'PD' * (j//2) + 'P'
  if T[j] == 'P':
    if j % 2 == 0:
      S += 'PD' * (j//2)
    else:
      S += 'DP' * (j//2) + 'D'
      
for k, c in enumerate(T[j:]):
  if c != '?':
    S += c
  if c == '?':
    if S[k-1] == 'P':
      S += 'D'
    else:
      if k+1 <= len(T[j:])-1 and T[k+1] == 'P':
        S += 'D'
      else:
        S += 'P'

print(S)