#include <bits/stdc++.h>
using namespace std;
const int SS = 5e2 + 123;
const int N = 1e5 + 123;
const int NN = 1e6 + 123;
const int M = 1e7 + 123;
const int MM = 1e8 + 123;
const int inf = 1e9 + 123;
const long long INF = 1e18 + 123;
const long long MAXN = 1e10 + 123;
const long long MOD = 1e9 + 7;
const long long mod = 555557;
const double pi = acos(-1.0);
int n, a[N], b[N], cnt;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    b[i] = a[i];
  }
  sort(b + 1, b + 1 + n);
  for (int i = 1; i <= n; i++) {
    if (a[i] != b[i]) cnt++;
  }
  if (cnt == 2 || !cnt)
    cout << "YES";
  else
    cout << "NO";
}
