#include<stdio.h>
#include<string.h>
int main(void)
{
	char T[200001];
	scanf("%s",T);
	int i=0;
	while(strncmp("\0",&T[i],1)!=0) {
		if(strncmp("?",&T[i],1)==0) {
			strncpy(&T[i],"D",1);
		}
		i++;
	}
	printf("%s\n",T);
	return 0;
}