def find_misplaced_elements(nums, n):
    max_length = 0
    first_num = 0
    second_num = 0
    minimums = [0] * n
    # minimums[-i] megmondja a leghatso i minimumat
    minimums[-1] = nums[-1]
    for i in range(n - 2, -1, -1):
        minimums[i] = min(minimums[i + 1], nums[i])
    for i in range(n - 1):
        # if minimums[i+1] >= nums[i]:
        #    continue
        if minimums[-1] < nums[i]:
            if n - 1 - i > max_length:
                max_length = n - 1 - i
                first_num = i
                second_num = n - 1
                continue
        lo = min(max_length + i + 1, n - 1)
        hi = n - 1
        if minimums[lo] >= nums[i]:
            continue
        while hi - lo > 1:
            mid = (lo + hi) // 2
            if minimums[mid] < nums[i]:
                lo = mid
            else:
                hi = mid
        max_length = lo - i
        first_num = i
        second_num = lo

    if max_length > 0:
        print(first_num + 1, second_num + 1)
    else:
        print(-1)


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

find_misplaced_elements(nums, n)