#include <sstream>
#include <string>
#include <vector>
#include <map>
#include <algorithm>
#include <iostream>
#include <utility>
#include <set>
#include <cctype>
#include <queue>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cmath>

#define INF 1000000000

using namespace std;
typedef long long ll;

int a[64];
bool visit[64];
int num[64];

int dfs(int s, int v) {
    visit[v] = true;
    if (s == v) return 1;
    return dfs(s, a[v]) + 1;
}

int main(void) {
    int N;
    cin >> N;
    int evenNum = 0;
    for (int i = 1; i <= N; i++) {
        cin >> a[i];
    }
    for (int i = 1; i <= N; i++) {
        if (visit[i]) continue;
        int tmp = dfs(i, a[i]);
        num[tmp]++;
//        cout << i << "  " << tmp << endl;
    }
    for (int i = 0; i < 30; i++) {
        if (num[i*2] % 2 == 1) {
            cout << "No" << endl;
            return 0;
        }
    }
    cout << "Yes" << endl;
    return 0;
}