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.*;
import java.io.*;

public class Solution {
	public static PrintWriter w = new PrintWriter(System.out);
	public static void main(String args[] ) throws Exception {
		Reader in = new Reader();
		int n = in.nextInt();
		int[] arr = in.nextIntArray(n);
		int[] arr1 = new int[n];
		int fi = 0, li = 0;
		boolean flag1 = false;
		for (int i=0; i<n; i++) {
			if(arr[i] != (i+1) && !flag1) {
				flag1 = true;
				int x = arr[i];
				int k = x;
				fi = i+1;li = arr[i];
				for (int j=i; j<x; j++,k--) {
					arr1[j] = k;
				}
				i = x-1;
			} else
				arr1[i] = i+1;
		}
		boolean flag = true;
		for (int i=0; i<n; i++) {
			if(arr[i] != arr1[i]) {
				flag = false;
				break;
			}
		}
		w.println(flag ? fi + " " + li : "0 0");
		w.flush();
		return;
	}
}

class Reader {
	final private int BUFFER_SIZE = 1 << 16;
	private DataInputStream din;
	private byte[] buffer;
	private int bufferPointer, bytesRead;

	public Reader() {
		din = new DataInputStream(System.in);
		buffer = new byte[BUFFER_SIZE];
		bufferPointer = bytesRead = 0;
	}
	public String nextLine() throws IOException {
		int c = read();
		while(isSpaceChar(c))
			c = read();
		StringBuilder res = new StringBuilder();
		do {
			res.appendCodePoint(c);
			c = read();
		} while(!isEndOfLine(c));
		return res.toString();
	}
	public String next() throws IOException {
		int c = read();
		while(isSpaceChar(c))
			c = read();
		StringBuilder res = new StringBuilder();
		do {
			res.appendCodePoint(c);
			c = read();
		} while(!isSpaceChar(c));
		return res.toString();
	}
	public int nextInt() throws IOException {
		int ret = 0;
		byte c = read();
		while(c <= ' ')
			c = read();
		boolean neg = (c == '-');
		if(neg)
			c = read();
		do {
			ret = ret * 10 + c - '0';
		} while((c = read()) >= '0' && c <= '9');
		if (neg)
			return -ret;
		return ret;
	}
	public int[] nextIntArray(int n) throws IOException {
		int a[] = new int[n];
		for(int i = 0; i < n; i++)
			a[i] = nextInt();
		return a;
	}
	public int[][] next2dIntArray(int n, int m) throws IOException {
		int a[][] = new int[n][m];
		for(int i = 0; i < n; i++)
			for(int j = 0; j < m; j++)
				a[i][j] = nextInt();
		return a;
	}
	public char nextChar() throws IOException {
		return next().charAt(0);
	}
	public long nextLong() throws IOException {
		long ret = 0;
		byte c = read();
		while(c <= ' ')
			c = read();
		boolean neg = (c == '-');
		if(neg)
			c = read();
		do {
			ret = ret * 10 + c - '0';
		} while((c = read()) >= '0' && c <= '9');
		if (neg)
			return -ret;
		return ret;
	}
	public double nextDouble() throws IOException {
		double ret = 0, div = 1;
		byte c = read();
		while(c <= ' ')
			c = read();
		boolean neg = (c == '-');
		if(neg)
			c = read();
		do {
			ret = ret * 10 + c - '0';
		} while((c = read()) >= '0' && c <= '9');
		if (c == '.') {
			while((c = read()) >= '0' && c <= '9') {
				ret += (c - '0') / (div *= 10);
			}
		}
		if(neg)
			return -ret;
		return ret;
	}
	private void fillBuffer() throws IOException {
		bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);
		if(bytesRead == -1)
			buffer[0] = -1;
	}
	private byte read() throws IOException {
		if(bufferPointer == bytesRead)
			fillBuffer();
		return buffer[bufferPointer++];
	}
	public void close() throws IOException {
		if(din == null)
			return;
		din.close();
	}
	public boolean isSpaceChar(int c) {
		return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
	}
	private boolean isEndOfLine(int c) {
		return c == '\n' || c == '\r' || c == -1;
	}
}