Problem:
Score : 800 points

Problem Statement

Takahashi and Aoki will play a game on a tree.
The tree has N vertices numbered 1 to N, and the i-th of the N-1 edges connects Vertex a_i and Vertex b_i.

At the beginning of the game, each vertex contains a coin.
Starting from Takahashi, he and Aoki will alternately perform the following operation:

Choose a vertex v that contains one or more coins, and remove all the coins from v.

Then, move each coin remaining on the tree to the vertex that is nearest to v among the adjacent vertices of the coin's current vertex.

The player who becomes unable to play, loses the game.
That is, the player who takes his turn when there is no coin remaining on the tree, loses the game.
Determine the winner of the game when both players play optimally.

Constraints

1 \leq N \leq 2 \times 10^5

1 \leq a_i, b_i \leq N

a_i \neq b_i

The graph given as input is a tree.

Input

Input is given from Standard Input in the following format:

N
a_1 b_1
a_2 b_2
:
a_{N-1} b_{N-1}

Output

Print First if Takahashi will win, and print Second if Aoki will win.

Sample Input 1

3
1 2
2 3

Sample Output 1

First

Here is one possible progress of the game:

Takahashi removes the coin from Vertex 1. Now, Vertex 1 and Vertex 2 contain one coin each.

Aoki removes the coin from Vertex 2. Now, Vertex 2 contains one coin.

Takahashi removes the coin from Vertex 2. Now, there is no coin remaining on the tree.

Aoki takes his turn when there is no coin on the tree and loses.

Sample Input 2

6
1 2
2 3
2 4
4 6
5 6

Sample Output 2

Second

Sample Input 3

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

Sample Output 3

First

Solution in C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

#define ALL(obj) (obj).begin(),(obj).end()
#define SPEED cin.tie(0);ios::sync_with_stdio(false);

template<class T> using PQ = priority_queue<T>;
template<class T> using PQR = priority_queue<T,vector<T>,greater<T>>;

constexpr long long MOD = (long long)1e9 + 7;
constexpr long long MOD2 = 998244353;
constexpr long long HIGHINF = (long long)1e18;
constexpr long long LOWINF = (long long)1e15;
constexpr long double PI = 3.1415926535897932384626433L;

template <class T> vector<T> multivector(size_t N,T init){return vector<T>(N,init);}
template <class... T> auto multivector(size_t N,T... t){return vector<decltype(multivector(t...))>(N,multivector(t...));}
template <class T> void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; exit(0);}}
template <class T, class U>ostream &operator<<(ostream &o, const map<T, U>&obj) {o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;}
template <class T>ostream &operator<<(ostream &o, const set<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const multiset<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;}
template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;}
template <template <class tmp>  class T, class U> ostream &operator<<(ostream &o, const T<U> &obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr)o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;}
void print(void) {cout << endl;}
template <class Head> void print(Head&& head) {cout << head;print();}
template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward<Tail>(tail)...);}
template <class T> void chmax(T& a, const T b){a=max(a,b);}
template <class T> void chmin(T& a, const T b){a=min(a,b);}
void YN(bool flg) {cout << (flg ? "YES" : "NO") << endl;}
void Yn(bool flg) {cout << (flg ? "Yes" : "No") << endl;}
void yn(bool flg) {cout << (flg ? "yes" : "no") << endl;}

template<class Operator> class Tree {
	Operator Op;                            
	using typeDist = decltype(Op.unitDist); 
	using typeLca = decltype(Op.unitLca); 
	size_t num;
	size_t ord;
public:
	vector<vector<pair<size_t,typeDist>>> edge;
	vector<size_t> depth;
	vector<size_t> order;
	vector<typeDist> dist;
	vector<pair<size_t,typeDist>> parent;
	vector<vector<pair<size_t,typeDist>>> child;
	vector<array<pair<size_t,typeLca>,Operator::bit>> ancestor;
	vector<size_t> size;
	Tree(const int num):num(num),edge(num),depth(num),order(num),dist(num){}
	//O(1) anytime
	void makeEdge(const int& from, const int& to, const typeDist w = 1) {
		edge[from].push_back({to,w});
	}
	//O(N) anytime
	void makeDepth(const int root) {
		depth[root] = 0;
		dist[root] = Op.unitDist;
		ord = 0;
		dfs1(root);
		order[ord++] = root;
	}
	//for makeDepth
	void dfs1(int curr, int prev = -1){
		for(auto& e:edge[curr]){
			int next = e.first;
			if(next==prev) continue;
			depth[next] = depth[curr] + 1;
			dist[next]  = Op.funcDist(dist[curr],e.second);
			dfs1(next,curr);
			order[ord++] = next;
		}
	}
	//O(N) after makeDepth
	void makeParent(void) {
		parent.resize(num);
		for (int i = 0; i < num; ++i) for (auto& e : edge[i]) if (depth[i] > depth[e.first]) parent[i] = e;
	}
	//O(N) after makeDepth
	void makeChild(void) {
		child.resize(num);
		for (int i = 0; i < num; ++i) for (auto& e : edge[i]) if (depth[i] < depth[e.first]) child[i].push_back(e);
	}
	//O(NlogN) after makeDepth and makeParent
	void makeAncestor(void) {
		ancestor.resize(num);
		for (int i = 0; i < num; ++i) ancestor[i][0] = parent[i];
		ancestor[order.back()][0] = make_pair(order.back(),Op.unitLca);
		for (int j = 1; j < Operator::bit; ++j) {
			for (int i = 0; i < num; ++i) {
				size_t k = ancestor[i][j - 1].first;
				ancestor[i][j] = Op.funcLca(ancestor[k][j - 1],ancestor[i][j - 1]);
			}
		}
	}
	//O(logN) after makeAncestor
	pair<size_t,typeLca> lca(size_t l, size_t r) {
		if (depth[l] < depth[r]) swap(l, r);
		int diff = depth[l] - depth[r];
		auto ancl = make_pair(l,Op.unitLca);
		auto ancr = make_pair(r,Op.unitLca);
		for (int j = 0; j < Operator::bit; ++j) {
			if (diff & (1 << j)) {
				ancl = Op.funcLca(ancestor[ancl.first][j],ancl);
			}
		}
		if(ancl.first==ancr.first) return ancl;
		for (int j = Operator::bit - 1; 0 <= j; --j) {
			if(ancestor[ancl.first][j].first!=ancestor[ancr.first][j].first) {
				ancl = Op.funcLca(ancestor[ancl.first][j],ancl);
				ancr = Op.funcLca(ancestor[ancr.first][j],ancr);
			}
		}
		ancl = Op.funcLca(ancestor[ancl.first][0],ancl);
		ancr = Op.funcLca(ancestor[ancr.first][0],ancr);
		return Op.funcLca(ancl,ancr);
	}
	//O(N) anytime
	int diameter(void){
		makeDepth(0);
		int tmp = max_element(depth.begin(), depth.end()) - depth.begin();
		makeDepth(tmp);
		return *max_element(depth.begin(), depth.end());
	}
};
template<class typeDist,class typeLca = typeDist> struct treeOperator{
	static const size_t bit = 20;
	typeDist unitDist = 0;
	typeDist unitLca = 0;
	typeDist funcDist(const typeDist& parent,const typeDist& w){return parent+w;}
	pair<size_t,typeDist> funcLca(const pair<size_t,typeDist>& l,const pair<size_t,typeDist>& r){return make_pair(l.first,l.second+r.second);}
};
 
//depth,dist
//https://atcoder.jp/contests/abc126/tasks/abc126_d
 
//lca
//https://atcoder.jp/contests/abc014/tasks/abc014_4
 
//child
//https://atcoder.jp/contests/abc133/tasks/abc133_e

//diameter
//https://atcoder.jp/contests/agc033/tasks/agc033_c

//eulerTour
//https://yukicoder.me/problems/no/900

// Tree<treeOperator<int>> tree(N);

int main() {
	int N; cin >> N;
	if(N==1){
		cout << "First" << endl;
		return 0;
	};
	Tree<treeOperator<int>> tree(N);
	for(int i = 0; i < N-1; ++i){
		int u,v; cin >> u >> v;
		u--,v--;
		tree.makeEdge(u,v);
		tree.makeEdge(v,u);
	}
	cout << (tree.diameter()%3==1?"Second":"First") << endl;
     return 0;
}