#include "bits/stdc++.h" using namespace std; typedef long long ll; typedef pair pii; typedef pair pll; const int INF = 1e9; const ll LINF = 1e18; template ostream& operator << (ostream& out,const pair& o){ out << "(" << o.first << "," << o.second << ")"; return out; } template ostream& operator << (ostream& out,const vector V){ for(int i = 0; i < V.size(); i++){ out << V[i]; if(i!=V.size()-1) out << " ";} return out; } template ostream& operator << (ostream& out,const vector > Mat){ for(int i = 0; i < Mat.size(); i++) { if(i != 0) out << endl; out << Mat[i];} return out; } template ostream& operator << (ostream& out,const map mp){ out << "{ "; for(auto it = mp.begin(); it != mp.end(); it++){ out << it->first << ":" << it->second; if(mp.size()-1 != distance(mp.begin(),it)) out << ", "; } out << " }"; return out; } /* 問題文============================================================ ================================================================= 解説============================================================= ================================================================ */ void dfs(ll n,int& cnt,vector& a,vector& f){ f[n] = 1; cnt++; if(f[a[n]] == 1) return; dfs(a[n],cnt,a,f); } string solve(){ ll N; cin >> N; vector a(N+1); for(int i = 1; i <= N;i++) cin >> a[i]; vector f(N+1,0); map mp; for(int i = 1; i <= N;i++){ if(f[i] == 1) continue; int cnt = 0; dfs(i,cnt,a,f); mp[cnt]++; } for(auto p:mp){ if(p.first%2 == 0 && p.second%2 == 1) return "No"; } return "Yes"; } int main(void) { cin.tie(0); ios_base::sync_with_stdio(false); cout << solve() << endl; return 0; }