#define _CRT_SECURE_NO_WARNINGS #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i)) #define rer(i,l,u) for(int (i)=(int)(l);(i)<=(int)(u);++(i)) #define reu(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i)) #if defined(_MSC_VER) || __cplusplus > 199711L #define aut(r,v) auto r = (v) #else #define aut(r,v) typeof(v) r = (v) #endif #define each(it,o) for(aut(it, (o).begin()); it != (o).end(); ++ it) #define all(o) (o).begin(), (o).end() #define pb(x) push_back(x) #define mp(x,y) make_pair((x),(y)) #define mset(m,v) memset(m,v,sizeof(m)) #define INF 0x3f3f3f3f #define INFL 0x3f3f3f3f3f3f3f3fLL using namespace std; typedef vector vi; typedef pair pii; typedef vector > vpii; typedef long long ll; typedef vector vl; typedef pair pll; typedef vector > vpll; typedef vector vs; typedef long double ld; template inline void amin(T &x, U y) { if(y < x) x = y; } template inline void amax(T &x, U y) { if(x < y) x = y; } int main() { int N; scanf("%d", &N); vector a(N); rep(i, N) scanf("%d", &a[i]), -- a[i]; vector vis(N); bool ans = true; vector cnt(N+1, 0); rep(i, N) if(!vis[i]) { int j = i, len = 0; do { vis[j] = true; ++ len; j = a[j]; }while(j != i); if(len % 2 == 0) ++ cnt[len]; } rep(i, N+1) ans &= cnt[i] % 2 == 0; puts(ans ? "Yes" : "No"); return 0; }