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 Main {
     FastScanner in = new FastScanner(System.in);    
     PrintWriter out = new PrintWriter(System.out);
     
     public static void main(String[]args){      
         new Main().solve();         
     }
     
     void solve(){
         
         int n = in.nextInt();
         ArrayList<Integer>Q = new ArrayList<Integer>();
         for (int i = 0; i<n; i++){
             Q.add(in.nextInt());
         }
         int G = 0;
         for (int i = 0; i<Q.size()-1; i++){
             if (Q.get(i) > Q.get(i+1)){
                 G = 1;
                 break;
             }
         }
         if (G==0){
             System.out.println(0+" "+0);return;
         }
         int index = -1; int len = -1;
         boolean f = false;
         for (int i = 0; i<n-1; i++){
             if (Q.get(i+1)<Q.get(i)){
                 if(!f){index = i;len = index+1;}
                 f = true;
             }
             else {
                 if (f == true){
                     len = i;
                     break;
                 }
             }
         }
         if (Q.size()>=2 && len<n-1)if (Q.get(Q.size()-1)<Q.get(Q.size()-2))len++;
         int l = index+1;
         int r = len+1;
         while (index<=len){
             int tmp = Q.get(index);
             Q.set(index, Q.get(len));
             Q.set(len, tmp);
             index++;
             len--;
         }
         for (int i = 0; i<n-1; i++){
             if (Q.get(i)>Q.get(i+1)){
                 System.out.println(0+" "+0); return;
             }
         }
         System.out.println(l + " " + r);
     }
}

///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

class FastScanner {
        BufferedReader br;
        StringTokenizer st;
        FastScanner(InputStream in) {
            br = new BufferedReader(new InputStreamReader(in));
        }
        String next() {
            while (st == null || !st.hasMoreTokens()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    System.err.println(e);
                    return "";
                }
            }
            return st.nextToken();
        }
        int nextInt() {
            return Integer.parseInt(next());
        }
        long nextLong() {
            return Long.parseLong(next());
        }
        double nextDouble() {
            return Double.parseDouble(next());
        }
        float nextFloat(){
            return Float.parseFloat(next());
        }
        void close() {
            try {
                br.close();
            } 
            catch (IOException e) {
            }
        }       
}
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////