#include<stdio.h>
int main()
{
char a,b;
while(scanf("%c %c",&a,&b)!=EOF)
{if(a=='D')
{if(b=='D')
printf("H\n");
else
printf("D\n");}
if(a=='H')
{if(b=='D')
printf("D\n");
else
printf("H\n");}}
return 0;
}