Problem: Vasya collects coins: he has exactly one coin for every year from 1 to n. Naturally, Vasya keeps all the coins in his collection in the order in which they were released. Once Vasya's younger brother made a change — he took all the coins whose release year dated from l to r inclusively and put them in the reverse order. That is, he took a certain segment [l, r] and reversed it. At that the segment's endpoints did not coincide. For example, if n = 8, then initially Vasya's coins were kept in the order 1 2 3 4 5 6 7 8. If Vasya's younger brother chose the segment [2, 6], then after the reversal the coin order will change to 1 6 5 4 3 2 7 8. Vasya suspects that someone else could have spoilt the permutation after his brother. Help him to find that out. Check if the given permutation can be obtained from the permutation 1 2 ... n using exactly one segment reversal. If it is possible, find the segment itself.

Input

The first line contains an integer n (1 ≤ n ≤ 1000) which is the number of coins in Vasya's collection. The second line contains space-separated n integers which are the spoilt sequence of coins. It is guaranteed that the given sequence is a permutation, i.e. it contains only integers from 1 to n, and every number is used exactly 1 time.

Output

If it is impossible to obtain the given permutation from the original one in exactly one action, print 0 0. Otherwise, print two numbers l r (1 ≤ l < r ≤ n) which are the endpoints of the segment that needs to be reversed to obtain from permutation 1 2 ... n the given one.

Examples

Input

8
1 6 5 4 3 2 7 8


Output

2 6


Input

4
2 3 4 1


Output

0 0


Input

4
1 2 3 4


Output

0 0

Solution (in JAVA):

Solution:
import java.awt.color.*;
import java.util.*;
import java.awt.Point;
import java.math.*;
import java.io.*;
@SuppressWarnings("unused")
public class implementation {int[] b;	String g="";int c=0;int M=1000000000+7;ArrayList<Integer> list=new ArrayList<Integer>();String s;int[] size;int[] id;
int[]ab;int[] data;int mod=100000;LinkedList<Integer> queue=new LinkedList<Integer>();int dis=0;int max=0;ArrayList<Integer>[] arr;
	public static void main(String[] args)  {
                new implementation().solve();
                                  }
	long[] fact;long[] inv;
            public void solve(){
            	int n=sc.nextInt();
            	list.add(0);
            	for(int i=1;i<=n;i++) {
            		list.add(sc.nextInt());
            	}
            	String s1="",s2="",s3="";int c=0,u=0;int yy=0;int zz=0;int kk=0;
            	
            	for(int i=1;i<=n;i++) {
            		if(list.get(i)!=i) {
            			c=i;u=list.get(i);yy=u;
            			for(int j=i+1;j<=u;j++) {
            				yy--;
            				if(list.get(j)!=yy)
            				{
            					zz=1;break;
            				}
            			}
            			for(int k=u+1;k<=n;k++) {
            				if(list.get(k)!=k) {
            					zz=1;break;}
            			}kk=1;
            		}
            		if(kk==1)
            			break;
            	}
            		
            	if(zz==1)
            		System.out.println(0+" "+0);
            	else {
            		System.out.println(c+" "+u);
            	}
            		
            }
            		
            public class Node{
       	     int x;int color;int y;
       	       Node par;
       	        public Node(int a,int b) {
       	          	x=a;color=b;
       		
       	             }
                         }
                     class sortbyweight implements Comparator<Node>{

       				@Override
       				public int compare(Node a, Node b) {
       					// TODO Auto-generated method stub
       					
       					if(a.color<b.color)
                			return 1;
                		else 
                			return -1;
       				}}
       				
       				 FastReader sc=new FastReader();
       				 static class FastReader
       				     {
       				         BufferedReader br;
       				         StringTokenizer st;
       				  
       				         public FastReader()
       				         {
       				             br = new BufferedReader(new
       				                      InputStreamReader(System.in));
       				         }
       				  
       				         String next()
       				         {
       				             while (st == null || !st.hasMoreElements())
       				             {
       				                 try
       				                 {
       				                     st = new StringTokenizer(br.readLine());
       				                 }
       				                 catch (IOException  e)
       				                 {
       				                     e.printStackTrace();
       				                 }
       				             }
       				             return st.nextToken();
       				         }
       				  
       				         int nextInt()
       				         {
       				             return Integer.parseInt(next());
       				         }
       				  
       				         long nextLong()
       				         {
       				             return Long.parseLong(next());
       				         }
       				  
       				         double nextDouble()
       				         {
       				             return Double.parseDouble(next());
       				         }
       				  
       				         String nextLine()
       				         {
       				             String str = "";
       				             try
       				             {
       				                 str = br.readLine();
       				             }
       				             catch (IOException e)
       				             {
       				                 e.printStackTrace();
       				             }
       				             return str;
       				         }
       				     }}