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: Accepted)

import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        Graph g = new Graph(n);
        for (int i = 0; i < n - 1; i++) {
            int a = sc.nextInt() - 1;
            int b = sc.nextInt() - 1;
            g.addPath(a, b);
        }
        ArrayList<Integer> ar = g.serchPath(0, n - 1);
        int len = ar.size();
        int Fennec = ar.get((len - 1) / 2);
        int Snuke = ar.get((len - 1) / 2 + 1);
        g.removePath(Snuke, Fennec);
        Fennec = g.countGroup(Fennec);
        Snuke = g.countGroup(Snuke);
        // len % 2 == 0 => Fenecスタート
        // len % 2 == 1 => Sunekeスタート
        if (len % 2 == 1) {
            Fennec++;
        }
        if (Snuke < Fennec) {
            System.out.println("Fennec");
        } else {
            System.out.println("Snuke");
        }
        sc.close();
    }
}

class Graph {

    int n;// node数

    Node[] nodes;

    /**
     * @param n:ノード数
     */
    Graph(int n) {
        this.n = n;
        nodes = new Node[n];
        for (int i = 0; i < n; i++) {
            nodes[i] = new Node(i);
        }
    }

    // 双方向pathの追加
    public void addPath(int v, int u) {
        this.nodes[u].addPath(nodes[v]);
        this.nodes[v].addPath(nodes[u]);
    }

    // pathの削除
    public void removePath(int u, int v) {
        this.nodes[u].removePath(nodes[v]);
        this.nodes[v].removePath(nodes[u]);
    }

    /**
     * @param v : node
     * @return count of this group7s node
     */
    public int countGroup(int v) {
        int cnt = 0;
        boolean[] visited = new boolean[n];
        ArrayDeque<Integer> stack = new ArrayDeque<Integer>();
        stack.push(v);
        cnt++;
        visited[v] = true;
        while (!stack.isEmpty()) {
            int pos = stack.poll();
            for (Node node : nodes[pos].edges) {
                if (!visited[node.id]) {
                    visited[node.id] = true;
                    cnt++;
                    stack.push(node.id);
                }
            }
        }
        return cnt;
    }

    public ArrayList<Integer> serchPath(int from, int to) {
        ArrayDeque<Integer> stack = new ArrayDeque<>();
        boolean[] visited = new boolean[n];
        stack.push(from);
        visited[from] = true;
        S: while (!stack.isEmpty()) {
            int currentPosition = stack.peekFirst();
            if (currentPosition == to) {
                break S;
            }
            for (Node n : nodes[currentPosition].edges) {
                if (!visited[n.id]) {
                    stack.push(n.id);
                    visited[n.id] = true;
                    continue S;
                }
            }
            stack.pollFirst();
        }
        ArrayList<Integer> path = new ArrayList<>(stack);
        Collections.reverse(path);
        return path;
    }

    class Node {
        int id;

        ArrayList<Node> edges;

        Node(int id) {
            this.id = id;
            this.edges = new ArrayList<>();
        }

        void addPath(Node next) {
            this.edges.add(next);
        }

        void removePath(Node other) {
            this.edges.remove(other);
        }
    }
}