#include<stdio.h>
#include<math.h>

int main(){
	char s[200000];
	scanf("%s", s);
	int count=0;
	int i = 0;
	while (s[i] != '\0') {
		if (s[i] == '?') {
			s[i] = 'D';
		}
		i++;
	}
	printf("%s\n", s);
	return 0;
}
