#include <bits/stdc++.h>
using namespace std;
typedef char* cstr;
const int oo = (~0u) >> 1;
const long long int ooll = (~0ull) >> 1;
const double inf = 1e8;
const double eps = 1e-8;
const double pi = acos(-1.0);
template <typename type>
inline bool cmax(type& a, const type& b) {
  return a < b ? a = b, true : false;
}
template <typename type>
inline bool cmin(type& a, const type& b) {
  return a > b ? a = b, true : false;
}
template <typename type>
inline type sqr(const type& first) {
  return first * first;
}
int dbcmp(const double& a, const double& b) {
  return (a > b + eps) - (a < b - eps);
}
int sgn(const double& first) { return dbcmp(first, 0); }
template <typename type>
inline type lb(type first) {
  return first & (-first);
}
template <typename type>
inline void bit_inc(vector<type>& st, int first, type inc) {
  while (first < ((int)(st).size())) st[first] += inc, first += lb(first);
}
template <typename type>
inline type bit_sum(const vector<type>& st, int first) {
  type s = 0;
  while (first > 0) s += st[first], first -= lb(first);
  return s;
}
inline void make_set(vector<int>& set, int size) {
  set.resize(size);
  for (int i = 0; i < (size); ++i) set[i] = i;
}
inline int find_set(vector<int>& set, int first) {
  if (set[first] != first) set[first] = find_set(set, set[first]);
  return set[first];
}
inline bool union_set(vector<int>& set, int a, int b) {
  a = find_set(set, a), b = find_set(set, b);
  return a == b ? false : set[a] = b, true;
}
int main() {
  int n;
  cin >> n;
  vector<int> a(n);
  for (int i = 0; i < (n); ++i) cin >> a[i];
  vector<int> b = a;
  sort((b).begin(), (b).end());
  int c = 0;
  for (int i = 0; i < (n); ++i)
    if (a[i] != b[i]) c++;
  if (c == 2 || c == 0)
    cout << "YES" << endl;
  else
    cout << "NO" << endl;
}
