import java.util.Scanner;
public class Main{
 public static void main(String[] args){
   Scanner sc = new Scanner(System.in);
   int N = sc.nextInt();
   int[] Ni = new int[N];
   for(int i = 0; i<N;i++)
   {
		Ni[i] = sc.nextInt();       
   }
   int count =0;
   for(int i = 0; i<N;i++)
   {
		if(Ni[i]-1 != i) count++;
   }
   if(count <=2)System.out.println("YES");
   else System.out.println("NO");
 }
} import java.util.Scanner; Scanner java.util public class Main{
 public static void main(String[] args){
   Scanner sc = new Scanner(System.in);
   int N = sc.nextInt();
   int[] Ni = new int[N];
   for(int i = 0; i<N;i++)
   {
		Ni[i] = sc.nextInt();       
   }
   int count =0;
   for(int i = 0; i<N;i++)
   {
		if(Ni[i]-1 != i) count++;
   }
   if(count <=2)System.out.println("YES");
   else System.out.println("NO");
 }
} Main public static void main(String[] args){
   Scanner sc = new Scanner(System.in);
   int N = sc.nextInt();
   int[] Ni = new int[N];
   for(int i = 0; i<N;i++)
   {
		Ni[i] = sc.nextInt();       
   }
   int count =0;
   for(int i = 0; i<N;i++)
   {
		if(Ni[i]-1 != i) count++;
   }
   if(count <=2)System.out.println("YES");
   else System.out.println("NO");
 } main {
   Scanner sc = new Scanner(System.in);
   int N = sc.nextInt();
   int[] Ni = new int[N];
   for(int i = 0; i<N;i++)
   {
		Ni[i] = sc.nextInt();       
   }
   int count =0;
   for(int i = 0; i<N;i++)
   {
		if(Ni[i]-1 != i) count++;
   }
   if(count <=2)System.out.println("YES");
   else System.out.println("NO");
 } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int[] Ni = new int[N]; Ni new int[N] N for(int i = 0; i<N;i++)
   {
		Ni[i] = sc.nextInt();       
   } int i = 0; int i = 0; i 0 i<N i N i++ i++ i {
		Ni[i] = sc.nextInt();       
   } {
		Ni[i] = sc.nextInt();       
   } Ni[i] = sc.nextInt() Ni[i] Ni i sc.nextInt() sc.nextInt sc int count =0; count 0 for(int i = 0; i<N;i++)
   {
		if(Ni[i]-1 != i) count++;
   } int i = 0; int i = 0; i 0 i<N i N i++ i++ i {
		if(Ni[i]-1 != i) count++;
   } {
		if(Ni[i]-1 != i) count++;
   } if(Ni[i]-1 != i) count++; Ni[i]-1 != i Ni[i]-1 Ni[i] Ni i 1 i count++ count if(count <=2)System.out.println("YES");
   else System.out.println("NO"); count <=2 count 2 System.out.println("YES") System.out.println System.out System System.out "YES" System.out.println("NO") System.out.println System.out System System.out "NO" String[] args args public class Main{
 public static void main(String[] args){
   Scanner sc = new Scanner(System.in);
   int N = sc.nextInt();
   int[] Ni = new int[N];
   for(int i = 0; i<N;i++)
   {
		Ni[i] = sc.nextInt();       
   }
   int count =0;
   for(int i = 0; i<N;i++)
   {
		if(Ni[i]-1 != i) count++;
   }
   if(count <=2)System.out.println("YES");
   else System.out.println("NO");
 }
} public class Main{
 public static void main(String[] args){
   Scanner sc = new Scanner(System.in);
   int N = sc.nextInt();
   int[] Ni = new int[N];
   for(int i = 0; i<N;i++)
   {
		Ni[i] = sc.nextInt();       
   }
   int count =0;
   for(int i = 0; i<N;i++)
   {
		if(Ni[i]-1 != i) count++;
   }
   if(count <=2)System.out.println("YES");
   else System.out.println("NO");
 }
} Main
import java.util.Scanner;
public class Main{
 public static void main(String[] args){
   Scanner sc = new Scanner(System.in);
   int N = sc.nextInt();
   int[] Ni = new int[N];
   for(int i = 0; i<N;i++)
   {
		Ni[i] = sc.nextInt();       
   }
   int count =0;
   for(int i = 0; i<N;i++)
   {
		if(Ni[i]-1 != i) count++;
   }
   if(count <=2)System.out.println("YES");
   else System.out.println("NO");
 }
}