#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

struct cvor
{
	int br;
	struct cvor *l, *d;
};

struct cvor *nadji( struct cvor *koren, int cvor )
{
	if ( koren == NULL ) return NULL;
	if ( koren -> br == cvor ) return koren;
	
	struct cvor *p = nadji( koren -> l, cvor );
	
	if ( p ) return p;
	
	return nadji( koren -> d, cvor );
}

void provera( struct cvor *koren, int brojOdKogaSviUPodstabluMorajuBitiManji, int brojOdKogaSviUPodstabluMorajuBitiVeci )
{
	if ( koren -> l )
		if ( koren -> l -> br < koren -> br && koren -> l -> br > brojOdKogaSviUPodstabluMorajuBitiVeci )
			provera( koren -> l, koren -> br , brojOdKogaSviUPodstabluMorajuBitiVeci );
		else printf("%d L\n", koren -> br );
	
	if ( koren -> d )
		if ( koren -> d -> br > koren -> br && koren -> d -> br < brojOdKogaSviUPodstabluMorajuBitiManji )
			provera( koren -> d, brojOdKogaSviUPodstabluMorajuBitiManji, koren -> br );
		else printf("%d D\n", koren -> br );
}

int main()
{
	int n, k;
	scanf("%d%d", &n, &k );
	struct cvor koren;
	koren.br = k;
	koren.l = koren.d = NULL;
	
	int cvor, naslednikLevi, naslednikDesni;
	scanf("%d", &cvor );
	while( cvor )
	{
		scanf("%d%d", &naslednikLevi, &naslednikDesni );
		
		struct cvor *stari = nadji( &koren, cvor );
		
		if ( naslednikLevi )
		{
			struct cvor *novi = ( struct cvor * ) malloc( sizeof( struct cvor ) );
			novi -> br = naslednikLevi;
			novi -> l = novi -> d = NULL;
			
			stari -> l = novi;
		}
		
		if ( naslednikDesni )
		{
			struct cvor *novi = ( struct cvor * ) malloc( sizeof( struct cvor ) );
			novi -> br = naslednikDesni;
			novi -> l = novi -> d = NULL;
			
			stari -> d = novi;
		}
		
		scanf("%d", &cvor );
	}
	
	provera( &koren, INT_MAX, -INT_MAX );
	
	return 0;
}