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.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.math.BigInteger;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Scanner;
import java.util.StringTokenizer;
import java.util.TreeMap;

public class Dragons {
	 
    static class Pair {
        int a;
        int b;
        public Pair(int a, int b){
            this.a=a;
            this.b=b;
        }
    }
	static ArrayList<Integer>[]adjList;
	static boolean[] color;
	static boolean visited[];
	static int count =0;
	public static void main(String[] args) throws IOException {
		Scanner sc=new Scanner(System.in);
		int n=sc.nextInt();
		boolean flag=false;
		boolean print=false;
		int l=0;
		int r=0;
		int arr[]=new int[n+1];
		for(int i=1;i<=n;i++) {
			arr[i]=sc.nextInt();
		}
		for(int i=1;i<=n;i++) {
			
			if(arr[i]!=i && arr[arr[i]]==i && flag==false) {
				
				l=i;
				r=arr[i];
				
				flag=true;
				i=arr[i]+1;
			}else if(arr[i]==i){
				continue;
				
			}else {
				print=true;
				System.out.println("0 0");
				flag=false;
				break;
			}
		}
		if(flag==false && print==false) {
			System.out.println("0 0");
		}else {
		if(flag) {
			for(int i=l;i<r;i++) {
				
				if(arr[i]==arr[i+1]+1) {
					continue;
				}else {
					System.out.println("0 0");
					flag=false;
					break;
				}
			}
			if(flag) {
				System.out.println(l+" "+r);
			}
		}
		}
	}

	
 
static class FastScanner {
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st=new StringTokenizer("");
		String next() {
			while (!st.hasMoreTokens())
				try {
					st=new StringTokenizer(br.readLine());
				} catch (IOException e) {
					e.printStackTrace();
				}
			return st.nextToken();
		}
		
		int nextInt() {
			return Integer.parseInt(next());
		}
		int[] readArray(int n) {
			int[] a=new int[n];
			for (int i=0; i<n; i++) a[i]=nextInt();
			return a;
		}
		long nextLong() {
			return Long.parseLong(next());
		}
	}
	
	
static void reduceFraction(int x, int y) 
{ 
    int d; 
    d = gcd(x, y); 
  
    x = x / d; 
    y = y / d; 
  if(x>0 && y<0) {
	  x=-x;
	  y=-y;
  }
    System.out.println( x + "/" + y); 
} 
	
	static int gcd(int a, int b) {
		return a%b == 0 ? b : gcd(b,a%b);
	}
	
	static boolean[] sieve(int n) {
		
		boolean isPrime[] = new boolean[n+1];
		for(int i = 2; i <= n; i++) {
			if(isPrime[i]) continue;
			for(int j = 2*i; j <= n; j+=i) {
				isPrime[j] = true;
			}
		
		}
		return isPrime;
		
	}
}