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:
def isCountinuous(sequence, difference):
	next_item = sequence[0]

	if not abs(next_item)%2:
		sequence.insert(len(sequence)/2, 0)

	for i in sequence:
		if i != next_item:
			return False
		else:
			next_item += difference
	return True

def main():
	n = input()

	data = [int(x) for x in raw_input().split()]
	default = range(1,n + 1)

	if data == default:
		print 0, 0
		return
	
	diff = []
	for i in range(n):
		if default[i] != data[i]:
			diff.append((i,data[i] - default[i]))

	numbers = [i[1] for i in diff]	
	numbers2 = list(reversed([-i for i in numbers]))

	if numbers == numbers2 and isCountinuous(numbers, -2):
		print diff[0][0] + 1, diff[-1][0] + 1
	else:
		print 0, 0
main()