#include<stdio.h>
int main()
{
	char t[200005];
	scanf("%s", t);
	int i, n = 0;
	while (t[n] != '\0')
		n++;
	for (i = 0; i < n; i++)
		if (t[i] == '?')
			t[i] = 'D';
	printf("%s\n", t);
	return 0;
}