def find_misplaced_elements(nums):
    n = len(nums)
    max_index = 0
    min_index = n - 1

    # Find the first misplaced element from the left
    for i in range(1, n):
        if nums[i] < nums[i - 1]:
            max_index = i - 1
            break

    # Find the first misplaced element from the right
    for i in range(n - 2, -1, -1):
        if nums[i] > nums[i + 1]:
            min_index = i + 1
            break

    # Check if the sequence is already sorted
    if max_index == 0 and min_index == n - 1:
        return -1

    return max_index+1, min_index+1

# Read input
n = int(input())
nums = list(map(int, input().split()))

# Find the indices of the misplaced elements
result = find_misplaced_elements(nums)

# Print the result
if result == -1:
    print(-1)
else:
    print(result[0], result[1])