#include<stdio.h>
#include<string>

int main(){
  char doctor[20000];
  int i;

  scanf("%s",doctor);
  
  for(i=0;i<sizeof(doctor);i++){
    if(doctor[i] == '?'){
      doctor[i] = 'D';
    }
  }
  printf("%s",doctor);
  return 0;
}