Problem:
Score : 400 points

Problem Statement

Fennec and Snuke are playing a board game.

On the board, there are N cells numbered 1 through N, and N-1 roads, each connecting two cells. Cell a_i is adjacent to Cell b_i through the i-th road. Every cell can be reached from every other cell by repeatedly traveling to an adjacent cell. In terms of graph theory, the graph formed by the cells and the roads is a tree.

Initially, Cell 1 is painted black, and Cell N is painted white. The other cells are not yet colored.
Fennec (who goes first) and Snuke (who goes second) alternately paint an uncolored cell.
More specifically, each player performs the following action in her/his turn:

Fennec: selects an uncolored cell that is adjacent to a black cell, and paints it black.

Snuke: selects an uncolored cell that is adjacent to a white cell, and paints it white.

A player loses when she/he cannot paint a cell. Determine the winner of the game when Fennec and Snuke play optimally.

Constraints

2 \leq N \leq 10^5

1 \leq a_i, b_i \leq N

The given graph is a tree.

Input

Input is given from Standard Input in the following format:

N
a_1 b_1
:
a_{N-1} b_{N-1}

Output

If Fennec wins, print Fennec; if Snuke wins, print Snuke.

Sample Input 1

7
3 6
1 2
3 1
7 4
5 7
1 4

Sample Output 1

Fennec

For example, if Fennec first paints Cell 2 black, she will win regardless of Snuke's moves.

Sample Input 2

4
1 4
4 2
2 3

Sample Output 2

Snuke

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.util.*;
import java.io.*;


public class Main{

    public static Node[] nodes;
    public static ArrayList<Node> fennecCanColor, snukeCanColor;
    public static boolean[] colored;

    public static void main(String[] args) throws Exception{
        
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter out = new PrintWriter(System.out);

        int n = Integer.parseInt(in.readLine());

        nodes = new Node[n+1];
        colored = new boolean[n+1];
        fennecCanColor = new ArrayList<Node>();
        snukeCanColor = new ArrayList<Node>();

        for(int i = 1; i <= n; i++){
            nodes[i] = new Node();
            nodes[i].num = i;
        }

        colored[1] = true;
        colored[n] = true;

        for(int i = 1; i < n; i++){
            String[] input = in.readLine().split("\\s+");
            int a = Integer.parseInt(input[0]);
            int b = Integer.parseInt(input[1]);

            nodes[a].adjList.add(nodes[b]);
            nodes[b].adjList.add(nodes[a]);

            nodes[a].canColorSize++;
            nodes[b].canColorSize++;

            if(a == 1 || a == n){
                nodes[b].canColorSize--;
            }

            if(b == 1 || b == n){
                nodes[a].canColorSize--;
            }

            if(a == 1 && b != n){
                fennecCanColor.add(nodes[b]);
            }
            else if(a == n && b != 1){
                snukeCanColor.add(nodes[b]);
            }

            if(b == 1 && a != n){
                fennecCanColor.add(nodes[a]);
            }
            else if(b == n && a != 1){
                snukeCanColor.add(nodes[a]);
            }
        }

        Collections.sort(fennecCanColor);
        Collections.sort(snukeCanColor);

        boolean fennec = true;;

        while(play(fennec)){
            fennec = !fennec;
        }

        if(fennec){
            out.println("Snuke");
        }
        else{
            out.println("Fennec");
        }

        in.close();
        out.close();
    }

    public static boolean play(boolean fennec){
        if(fennec){
            return playFennec();
        }
        return playSnuke();
    }

    public static boolean playFennec(){

        int size = fennecCanColor.size();

        if(size == 0){
            return false;
        }

        boolean canColor = false;

        for(int i = 0; i < size; i++){
            Node tmpNode = fennecCanColor.get(i);
            if(snukeCanColor.contains(tmpNode)){
                //System.out.println("Fennec colors: " + tmpNode.num);
                colored[tmpNode.num] = true;
                fennecCanColor.remove(i);
                snukeCanColor.remove(tmpNode);
                canColor = true;
                addAdjList(tmpNode.num, true);
                break;
            }
        }

        if(!canColor){
            Node tmpNode = fennecCanColor.get(0);
            //System.out.println("Fennec colors: " + fennecCanColor.get(0).num);
            colored[tmpNode.num] = true;
            canColor = true;
            addAdjList(fennecCanColor.get(0).num, true);
            fennecCanColor.remove(0);
        }

        return canColor;
    }

    public static boolean playSnuke(){

        int size = snukeCanColor.size();

        if(size == 0){
            return false;
        }

        boolean canColor = false;

        for(int i = 0; i < size; i++){
            Node tmpNode = snukeCanColor.get(i);
            if(fennecCanColor.contains(tmpNode)){
                //System.out.println("Snuke colors: " + tmpNode.num);
                colored[tmpNode.num] = true;
                snukeCanColor.remove(i);
                fennecCanColor.remove(tmpNode);
                canColor = true;
                addAdjList(tmpNode.num, true);
                break;
            }
        }

        if(!canColor){
            Node tmpNode = snukeCanColor.get(0);
            //System.out.println("Snuke colors: " + snukeCanColor.get(0).num);
            colored[tmpNode.num] = true;
            canColor = true;
            addAdjList(snukeCanColor.get(0).num, true);
            snukeCanColor.remove(0);
        }

        return canColor;
    }

    public static void addAdjList(int num, boolean fennec){
        if(fennec){
            for(Node node : nodes[num].adjList){
                node.canColorSize--;
                if(!colored[node.num]){
                    //System.out.println("\tFennec adds: " + node.num);
                    fennecCanColor.add(node);
                }
            }
        }
        else{
            for(Node node : nodes[num].adjList){
                if(!colored[node.num]){
                    //System.out.println("\tSnuke adds: " + node.num);
                    snukeCanColor.add(node);
                }
            }
        }

        Collections.sort(fennecCanColor);
        Collections.sort(snukeCanColor);
    }
}

class Node implements Comparable<Node> {

    public int num;
    public int canColorSize;
    public ArrayList<Node> adjList;

    public Node(){
        adjList = new ArrayList<Node>();
        canColorSize = 0;
    }

    @Override
    public int compareTo(Node n){
        return -1 * Integer.compare(this.canColorSize, n.canColorSize);
    }

}