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.util.Random;
import java.util.Arrays;
import java.util.StringTokenizer;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.PrintWriter;
import java.io.InputStreamReader;
import java.io.File;
import java.math.BigInteger;

public class Task{
	
	static final boolean readFromFile = false;
	static final String fileInputName = "input.txt",
						fileOutputName = "output.txt";
	
	public static void main(String args[]){
		FileInputStream fileInputStream;
		FileOutputStream fileOutputStream;
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		if (readFromFile){
			try{
				fileInputStream = new FileInputStream(new File(fileInputName));
				fileOutputStream = new FileOutputStream(new File(fileOutputName));
			}catch (FileNotFoundException e){
				throw new RuntimeException(e);
			}
		}
		PrintWriter out = new PrintWriter((readFromFile)?fileOutputStream:outputStream);
		InputReader in  = new InputReader((readFromFile)?fileInputStream:inputStream);
		
		Solver s = new Solver(in, out);
		s.solve();
		
		out.close();
	}
}

class Solver{
	private PrintWriter out;
	private InputReader in;
	
	int a[],n;
	
	boolean isNorm(){
		for (int i=0;i<n;i++)
			if (a[i]!=i+1)
				return false;
		return true;
	}
	
	public void solve(){
		n = in.nextInt();
		a = new int[n];
		for (int i=0;i<n;i++)
			a[i] = in.nextInt();
		if (isNorm()){
			out.println("0 0");
			return;
		}
		int l = 0,
			r = 0;
		for (int i=0;i<n;i++)
			if (a[i]!=i+1){
				l = i;
				r = a[i]-1;
				break;
			}
		int ll = l,
			rr = r;
		while (ll<rr){
			int buf = a[ll];
			a[ll]=a[rr];
			a[rr]=buf;
			ll++;rr--;
		}
		if (isNorm())
			out.println((l+1)+ " " + (r+1));
		else
			out.println("0 0");
	}
	
	Solver(InputReader in, PrintWriter out){
		this.in = in;
		this.out = out;
	}
}

class InputReader{
	StringTokenizer tok;
	BufferedReader buf;
	
	InputReader(InputStream in){
		tok = null;
		buf = new BufferedReader(new InputStreamReader(in));
	}

	InputReader(FileInputStream in){
		tok = null;
		buf = new BufferedReader(new InputStreamReader(in));
	}
	
	public String next(){
		while (tok==null || !tok.hasMoreTokens()){
			try{
				tok = new StringTokenizer(buf.readLine());
			}catch (IOException e){
				throw new RuntimeException(e);
			}
		}
		return tok.nextToken();
	}
	
	public int nextInt(){
		return Integer.parseInt(next());
	}
	public long nextLong(){
		return Long.parseLong(next());
	}
	public double nextDouble(){
		return Double.parseDouble(next());
	}
	public float nextFloat(){
		return Float.parseFloat(next());
	}
	public String nextLine(){
		try{
			return buf.readLine();
		}catch (IOException e){
			return null;
		}
	}
}