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.
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.
import sys
input = sys.stdin.readline

n = int(input())
a = list(map(int, input().split()))

pos = []
i = 0
while i < n and a[i] == i+1:
    i += 1
if i == n:
    print(0, 0)
else:
    pos.append(i+1)
    sn = a[i]
    j = 0
    while i < n and a[i] == sn-j:
        i += 1
        j += 1
    pos.append(i)
    j = 1
    while i < n:
        if a[i] != sn+j:
            print(0, 0)
            break
        i += 1
        j += 1
    else:
        print(pos[0], pos[1])