def rotate_by_pos(lst, pos):
    n = len(lst)
    return lst[n - pos: n] + lst[0:n - pos]


def binary_search(lst, el):
    first, last = 0, len(lst) - 1
    while first <= last:
        midpoint = (first + last) // 2
        if lst[midpoint] == el:
            return midpoint
        else:
            if lst[midpoint] > el >= lst[first]:
                last = midpoint - 1
            else:
                first = midpoint + 1
    return -1


if __name__ == "__main__":
    arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
    assert (binary_search(arr, 4) == 3)
    assert (binary_search(rotate_by_pos(arr, 1), 4) == 4)
    assert (binary_search(rotate_by_pos(arr, 2), 4) == 5)
    assert (binary_search(rotate_by_pos(arr, 6), 4) == 9)
    assert (binary_search(rotate_by_pos(arr, 7), 4) == 0)