#include using namespace std; int main() { int N; cin >> N; vector A(N); for (int i = 0; i < N; i++) { cin >> A[i]; } sort(A.begin(), A.end()); for (int i = 1; i <= N; i++) { if (i < A[i - 1]) { cout << "No"; return 0; } } cout << "Yes"; }