#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int (i) = 0 ; (i) < (int)(n) ; (i)++)
#define REP(i,a,b) for(int (i) = a ; (int)(i) <= (int)(b) ; (i)++)
#define all(n) (n).begin(),(n).end()

int main(){
	int n;
	cin >> n;
	vector<int> a(n);
	int c = 0;
	rep(i,n) cin >> a[i];
	rep(i,n) rep(j,n-i-1) if( a[j] > a[j+1] ) swap(a[j],a[j+1]),c++; 

	cout << (c%2?"No":"Yes") << endl; 
}