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 PYTHON3):

Solution:
n = int(input())

list_str = input().split(" ")
list = [int(l) for l in list_str]

phase = 1
droite = 0
gauche = 0
aux = True

for i in range (-1,n) :
    #print(i,phase)
    if i == -1 :
        g = 0
        d = list[i+1]
    elif i == n-1 :
        g = list[i]
        d = n+1
    else :
        g = list[i]
        d = list[i+1]
        
    if phase == 1 :
        if g+1 < d :
            phase = 2
            droite = d
        elif g+1 > d :
            aux = False
            break
    elif phase == 2 :
        if g-1 < d :
            phase = 3
            gauche = g
        elif g-1 > d :
            aux = False
            break
    elif phase == 3 :
        if g+1 != d :
            aux = False
            break
            
if aux :
    print(str(gauche) + " " + str(droite))
else :
    print("0 0")