golden_middle

# Используем полуинервал, не включаем right.
# Возвращаем две серединные точки, если в массиве нечётное количество элементов,
# то это одна и та же точка.
def get_middles(left, right):
    mid_left = (left + right - 1) // 2
    mid_right = (left + right) // 2
    return mid_left, mid_right


def find_median(a, b):
    if len(a) > len(b):
        a, b = b, a
    left_a = left_b = 0
    right_a = len(a)
    right_b = len(b)
    while True:
        mid_a_left, mid_a_right = get_middles(left_a, right_a)
        mid_b_left, mid_b_right = get_middles(left_b, right_b)
        offset = mid_a_left - left_a
        if offset == 0:   # осталось не больше 2-х элементов
            break
        if a[mid_a_left] <= b[mid_b_left] and b[mid_b_right] <= a[mid_a_right]:
            return (b[mid_b_left] + b[mid_b_right]) / 2
        elif b[mid_b_left] <= a[mid_a_left] and a[mid_a_right] <= b[mid_b_right]:
            return (a[mid_a_left] + a[mid_a_right]) / 2
        elif b[mid_b_right] <= a[mid_a_right]:   # сдвигаем в a справа
            right_a -= offset
            left_b += offset
        else:   # a[mid_a_left] < b[mid_b_left], сдвигаем в a слева
            left_a += offset
            right_b -= offset
    offset = int(left_b < mid_b_left)   # offset равен единице, если в b осталось
                                        # больше 2-х элементов.
    c = sorted(a[left_a:right_a] + b[mid_b_left-offset: mid_b_right+offset+1])
    mid_c_left, mid_c_right = get_middles(0, len(c))
    return (c[mid_c_left] + c[mid_c_right]) / 2


input()
input()
nord_amounts = [int(x) for x in input().split()]
south_amounts = [int(x) for x in input().split()]
print(find_median(nord_amounts, south_amounts))