#include <iostream>
using namespace std;

int n, a[50], b[51];
// b[j] := 大きさ j のループの個数

int loop_size(int i) {
	if (a[i] == -1) return 0;
	int next = a[i];
	a[i] = -1;
	return loop_size(next) + 1;
}

bool solve() {
	for (int i = 0; i < n; i++)
		if (a[i] != -1)
			b[loop_size(i)]++;
	// 偶数サイズのループが奇数個あれば false
	for (int j = 2; j <= n; j += 2)
		if (b[j] % 2 == 1)
			return false;
	return true;
}

int main() {
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> a[i];
		a[i]--;
	}
	cout << (solve() ? "Yes" : "No") << endl;
}