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 PYTHON):

Solution:

# -*- coding: UTF-8 -*-

# from itertools import *
# from collections import defaultdict

# def gcd(a,b):
#     while b > 0: a,b = b, a%b
#     return a

# def baseN(num,b,numerals="0123456789abcdefghijklmnopqrstuvwxyz"):
#     return ((num == 0) and  "0" ) or ( baseN(num // b, b).lstrip("0") + numerals[num % b])

T = input()
# St = raw_input()
data1 = map(int, raw_input().split())
# data2 = [ map(int, raw_input().split()) for i in xrange(T) ]
l = r = -1
for i in xrange(len(data1)):
    if data1[i] != i+1:
        r = i
    if data1[len(data1)-1-i] != len(data1)-i:
        l = len(data1)-i-1
for i in xrange(l, r):
    if data1[i] != data1[i+1] + 1:
        print 0, 0
        exit()
        
print l+1, r+1