#include <bits/stdc++.h> using namespace std; /*^ debug */ template <typename A, typename B> string to_string(pair<A, B> p); template <typename A, typename B, typename C> string to_string(tuple<A, B, C> p); template <typename A, typename B, typename C, typename D> string to_string(tuple<A, B, C, D> p); string to_string(const string& s) { return '"' + s + '"'; } string to_string(const char* s) { return to_string((string) s); } string to_string(bool b) { return (b ? "true" : "false"); } string to_string(vector<bool> v) { bool first = true; string res = "{"; for (int i = 0; i < static_cast<int>(v.size()); i++) { if (!first) { res += ", "; } first = false; res += to_string(v[i]); } res += "}"; return res; } template <size_t N> string to_string(bitset<N> v) { string res = ""; for (size_t i = 0; i < N; i++) { res += static_cast<char>('0' + v[i]); } return res; } template <typename A> string to_string(A v) { bool first = true; string res = "{"; for (const auto &x : v) { if (!first) { res += ", "; } first = false; res += to_string(x); } res += "}"; return res; } template <typename A, typename B> string to_string(pair<A, B> p) { return "(" + to_string(p.first) + ", " + to_string(p.second) + ")"; } template <typename A, typename B, typename C> string to_string(tuple<A, B, C> p) { return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ")"; } template <typename A, typename B, typename C, typename D> string to_string(tuple<A, B, C, D> p) { return "(" + to_string(get<0>(p)) + ", " + to_string(get<1>(p)) + ", " + to_string(get<2>(p)) + ", " + to_string(get<3>(p)) + ")"; } void debug_out() { cerr << endl; } template <typename Head, typename... Tail> void debug_out(Head H, Tail... T) { cerr << " " << to_string(H); debug_out(T...); } #ifdef LOCAL #define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__) #else #define debug(...) 42 #endif /* debug $*/ /*^ generic definitions */ template<typename F> struct _RecurFun : F { _RecurFun(F&& f) : F(forward<F>(f)) {} template<typename... Args> decltype(auto) operator()(Args&&... args) const { return F::operator()(*this, forward<Args>(args)...); } }; template<typename F> decltype(auto) RecurFun(F&& f) { return _RecurFun<F> { forward<F>(f) }; } /* generic definitions $*/ int main() { ios::sync_with_stdio(false); int N; { cin >> N; } vector<int> A(N); { for (int i = 0; i < N; ++i) cin >> A[i], --A[i]; } int evenCycCnt = 0; { vector<int> vis(N); for (int i = 0; i < N; ++i) if (!vis[i]) { int c = 0; for (int j = i; !vis[j]; j = A[j]) { ++c; vis[j] = 1; } evenCycCnt += c % 2 == 0; } } cout << (evenCycCnt % 2 == 0 ? "Yes" : "No") << endl; }