#include "bits/stdc++.h"
using namespace std;

int unidp[100];

int findunidp(int a){
	if (unidp[a] < 0) return a;
	else return unidp[a] = findunidp(unidp[a]);
}

bool connect(int a, int b){
	a = findunidp(a);
	b = findunidp(b);
	if (a == b) return false;
	unidp[a] += unidp[b];
	unidp[b] = a;
	return true;
}

int main(){
	int N;
	cin >> N;
	vector<int> V(N);
	for (int i = 0; i < N; i++)
	{
		cin >> V[i]; V[i]--;
		unidp[i] = -1;
	}
	for (int i = 0; i < N; i++)
	{
		connect(i, V[i]);
	}
	
	map<int, int> m;
	for (int i = 0; i < N; i++)
	{
		if (unidp[i] >= 0) continue;
		int loop = -unidp[i];
		m[loop] += 1;
	}
	for (auto i : m){
		if (i.first % 2 != 0) continue;
		if (i.second % 2 != 0){
			cout << "No" << endl;
			return 0;
		}
	}
	cout << "Yes" << endl;
}