#include <bits/stdc++.h>
using namespace std;

int main(void) {
	int N;
	cin >> N;
	vector<int> A(N);
	for(int i = 0; i < N; ++i) cin >> A[i];
	
	int cnt = 0;
	for(int i = 0; i < N; ++i) for(int j = i + 1; j < N; ++j) if(A[i] > A[j]) cnt += 1;
	
	cout << (cnt % 2 == 0 ? "Yes" : "No") << "\n";
	
	return 0;
}