#include <iostream>

#define REP(i,s,n) for(int i=(int)(s);i<(int)(n);i++)

using namespace std;
typedef long long int ll;


int a[51];
int main(void){
  int n;
  cin >> n;
  int c = 0;
  REP(i, 0, n) {
    cin >> a[i];
    --a[i];
  }
  REP(i, 0, n) {
    int v = a[i];
    int c = 1;
    while (v != i) {
      v = a[v];
      c++;
    }
    if (c % 2 == 0) {
      cout << "No" << endl;
      return 0;
    }
  }
  cout << "Yes" << endl;
}