Problem Related to graphs

I am doing this question in URI Online Judge .

I'm trying with DFS, but by now I did not get anything.

I put a variable to mark it up to the level it goes and when it reaches that level it comes back, but it is returning the wrong outputs.

I'm wondering if I'd use a BFS or DFS here, which would be better? Am I doing it right?

package Rerisson_e_o_Churrasco.copy;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;
import java.util.Map.Entry;
/**
 * IMPORTANT: 
 *      O nome da classe deve ser "Main" para que a sua solução execute
 *      Class name must be "Main" for your solution to execute
 *      El nombre de la clase debe ser "Main" para que su solución ejecutar
 */

    public class Main{
        int qtdVertice;
        int nivel;
        Map<String,ArrayList<String>> Ar = new HashMap<>();
        public Main(int qtdVertice, int nivel){
            this.qtdVertice = qtdVertice;
            this.nivel = nivel;
        }


        public void add_Aresta(String Origem, String Destino){
            if(Ar.containsKey(Origem)){
                Ar.get(Origem).add(Destino);
            }else{
                ArrayList<String> a= new ArrayList<>();
                a.add(Destino);
                Ar.put(Origem,a);
            }
        }
        public int DFS(int contador, String S, ArrayList resposta){
            if(!resposta.contains(S))
                resposta.add(S);
            if(contador == nivel) {
                return contador;
            }
            if(Ar.containsKey(S)) {
                for(String a : Ar.get(S)) {
                    DFS(contador++,a,resposta);
                }
            }
            return contador--;


        }
        public void DFS_init(String nome) {
            int contador = 0;
            ArrayList<String> resposta = new ArrayList<>();
            DFS(contador, nome, resposta);
            resposta.remove(nome);
            Collections.sort(resposta);

            System.out.println(resposta.size());
            for(String b : resposta) {
                System.out.println(b);
            }

        }
        public static void main(String arg[]) {
            Scanner sc = new Scanner(System.in);
            int n;
            int G;
            String S;
            String T;
            String inicio = null;
            String a[] = new String[2];
            a = sc.nextLine().split(" ");
            n = Integer.parseInt(a[0]);
            G = Integer.parseInt(a[1]);
            Main teste = new Main(n,G);
            for(int i = 0; i < n; i++){
                a = sc.nextLine().split(" ");
                S = a[0];
                T = a[1];
                if(i == 0) {
                    inicio = S;
                }
                teste.add_Aresta(S, T);
            }
            teste.DFS_init(inicio);


        }

    }