A = [1, 2, 3, 5]


def range_lookup(A):
    return []


def sum_series(A):
    N = len(A) + 1
    return (N ** 2 + N) // 2 - sum(A)


sum_series(A)

4972164c72c34a96f24cc41da13a7efdf376da95
<mask token>


def range_lookup(A):
    return []


<mask token>

<mask token>


def range_lookup(A):
    return []


def sum_series(A):
    N = len(A) + 1
    return (N ** 2 + N) // 2 - sum(A)


<mask token>

<mask token>


def range_lookup(A):
    return []


def sum_series(A):
    N = len(A) + 1
    return (N ** 2 + N) // 2 - sum(A)


sum_series(A)

A = [1, 2, 3, 5]


def range_lookup(A):
    return []


def sum_series(A):
    N = len(A) + 1
    return (N ** 2 + N) // 2 - sum(A)


sum_series(A)
