def readlist():
    return list(map(int, input().split()))


def readint():
    return map(int, input().split())


n = int(input())
coord = readlist()
plus, minus = [0], [0]
for x in coord:
    if x > 0:
        plus.append(x)
    elif x < 0:
        minus.append(x)
plus.sort()
minus.sort()
print(plus[-1] * 2 - minus[0] * 2)