#include #include #include #include #include #include #include #include #include #include #include #include #include #include #define INF 1000000000 using namespace std; typedef long long ll; int a[64]; int b[64]; bool visit[64]; int dfs(int s, int v) { visit[v] = true; if (s == v) return 1; return dfs(s, b[v]) + 1; } int main(void) { int N; cin >> N; int evenNum = 0; for (int i = 1; i <= N; i++) { cin >> a[i]; b[a[i]] = i; } for (int i = 1; i <= N; i++) { if (visit[i]) continue; int tmp = dfs(i, b[i]); if (tmp % 2 == 0) evenNum++; } if (evenNum % 2 == 0) cout << "Yes" << endl; else cout << "No" << endl; return 0; }