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.*;
    import java.util.*;
    import static java.lang.Math.*;

    public class timelly {

        final boolean ONLINE_JUDGE = true;

        BufferedReader in;
        PrintWriter out;
        StringTokenizer tok = new StringTokenizer("");

        void init() throws IOException {
            if (ONLINE_JUDGE) {
                in = new BufferedReader(new InputStreamReader(System.in));
                out = new PrintWriter(System.out);
            } else {
                in = new BufferedReader(new FileReader("input.txt"));
                out = new PrintWriter("output.txt");
            }
        }

        String readString() throws IOException {
            while (!tok.hasMoreTokens()) {
                tok = new StringTokenizer(in.readLine());
            }
            return tok.nextToken();
        }

        int readInt() throws IOException {
            return Integer.parseInt(readString());
        }

        long readLong() throws IOException {
            return Long.parseLong(readString());
        }

        double readDouble() throws IOException {
            return Double.parseDouble(readString());
        }

        void debug(Object o) {
            System.err.println(o.toString());
        }

        void run() {
            try {
                long t1 = System.currentTimeMillis();
                init();
                solve();
                out.close();
                long t2 = System.currentTimeMillis();
                debug("Time = " + (t2 - t1));
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }

        public static void main(String[] args) {
            (new timelly()).run();
        }

        void solve() throws IOException {
            int n = readInt();
            int[] a = new int[n+10];
            for (int i=0; i<n; i++) {
                a[i] = readInt();
            }
            int min=0, max=n-1,x=0;
            for (int i=0; i<n-1; i++) {
                if (a[i]-1==a[i+1]) {
                    max=a[i]-1;
                    min=a[max]-1;
                    break;
                }
            }
            for (int i=min; i<=(max+min)/2; i++) {
                x=a[i];
                a[i]=a[max+min-i];
                a[max+min-i]=x;
            }
            
            boolean f=true;
            for (int i=0; i<n-1; i++) {
                if(a[i]+1!=a[i+1]) {
                    f=false;
                    break;
                }
            }
            
            
            if ((f) & (n!=1)) {
                out.print(min+1);
                out.print(" ");
                out.println(max+1);
            } else {
                out.print(0);
                out.print(" ");
                out.println(0);
            }
        }

    }