import sys

for line in sys.stdin:
    pices = int(line)

    if (pices == 0):
        print(0)
        exit()

    arr = list()
    arr = map(int, input().split())

    ar = sorted(arr)

    half = ar[pices-1] / 2

    i = 0
    index = 0
    closest = 1001

    if (pices == 1):
        print(ar[0])
        exit()

    while ar[i] <= half:
        i += 1

    if i > 0:
        if (ar[i] - half) <= closest:
            closest = (ar[i] - half)
            index = i
        if (half - ar[i-1]) <= closest:
            closest = (ar[i-1] - half)
            index = i-1
    else:
        index = 0

    print(max((ar[pices-1] - ar[index]), ar[index]))