/* -*- coding: utf-8 -*-
 *
 * 3069.cc:  No.3069 Invisible Speedrun - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

const char dcs[] = "DR";
enum { D, R };

/* typedef */

/* global variables */

/* subroutines */

int query(int di) {
  putchar(dcs[di]); putchar('\n'); fflush(stdout);

  int v;
  scanf("%d", &v);
  if (v < 0) exit(0);
  return v;
}

/* main */

int main() {
  int n;
  scanf("%d", &n);

  for (int di = D;; di ^= 1) {
    int v = query(di);
    if (v) break;
  }

  //for (int i = 0; i < 1e9; i++);
  return 0;
}