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

#define rep(i,n) repi(i,0,n)
#define repi(i,a,b) for(int i=int(a);i<int(b);++i)

int n, a[50];

void input()
{
    cin >> n;
    rep(i, n) cin >> a[i], --a[i];
}

class disjoint_set
{
    vector<int> p;
public:
    disjoint_set(int n) : p(n, -1) {}
    int root(int i) { return p[i] >= 0 ? p[i] = root(p[i]) : i; }
    int size(int i) { return -p[root(i)]; }
    bool same(int i, int j) { return root(i) == root(j); }
    void merge(int i, int j) {
        i = root(i), j = root(j);
        if (i != j) {
            if (p[i] > p[j]) swap(i, j);
            p[i] += p[j], p[j] = i;
        }
    }
};

bool solve()
{
    disjoint_set uf(n);
    rep(i, n) uf.merge(i, a[i]);
    vector<int> odd(n+1);
    rep(i, n) if (uf.root(i) == i) {
        if (uf.size(i) % 2 == 0) {
            odd[uf.size(i)] ^= 1;
        }
    }
    return accumulate(begin(odd), end(odd), 0) == 0;
}

int main()
{
    cin.tie(0);
    ios_base::sync_with_stdio(false);

    input();
    cout << (solve() ? "Yes" : "No") << endl;
}