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.
def crs(v,n,r,l):
	if r<=l:
		return 0
	for c in range(l,r):
		if v[c]-v[c+1]!=1:
			return 0
	return 1

def gfl(v,n):
	r,l=0,0
	c,b=0,0
	while c<n:
		if v[c]!=c+1:
			if not crs(v,n,v[c]-1,c) or b:
				return 0,0
			b,r,l=1,v[c],c+1
			c=v[c]-1
		c+=1
	return l,r

input()
v=[int(x) for x in input().split()]
l,r=gfl(v,len(v))
print(l,r)