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

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N; cin >> N;
    vector<int> A(N);
    for(auto &a : A) cin >> a;

    int now = 0;
    for(int i=0; i<N; i++) for(int k=i+1; k<N; k++){
        now += A.at(i)>A.at(k);
    }
    cout << (now%2?"No":"Yes") << "\n";
}