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 math
n=int(input())
lst = list(map(int, input().strip().split(' ')))
l=-1
r=-1
k=0
if n%2==0:
    k=n//2
else:
    k=n//2 + 1
for i in range(k):
    if l==-1 and lst[i]!=i+1:
        l=i
    if r==-1 and lst[n-i-1]!=n-i:
        r=n-i-1
    if l!=-1 and r!=-1:
        break
if l==-1 and r==-1:
    print('0 0')
else:
    f=0
    p=r+1
    
    for j in range(l,r+1):
        if lst[j]==p:
            p-=1
        else:
            f=1
            break
    if f==1:
        print('0 0')
    else:
        print(l+1,r+1,end=" ")
        
