#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1 * 1000 + 10;
int ans[MAXN][MAXN];
int main() {
  ios::sync_with_stdio(false);
  int n, d, k;
  cin >> n;
  vector<int> a(n), b(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    b[i] = a[i];
  }
  sort(a.begin(), a.end(), [&](int a, int b) { return a <= b; });
  int ct = 0;
  for (int i = 0; i < n; i++) ct = (a[i] == b[i]) ? ct : ct + 1;
  if (ct == 0 || ct == 2)
    cout << "YES";
  else
    cout << "NO";
}
