3

-525187879 0 425880698

a = int(input())

def solve(t):
    coins = 0
    for i in range(len(t)):
        if t[i]==1 or t[i] ==-1:
            pass
        else:
            if t[i]<0:
                coins+=-1 - t[i]
                t[i] = -1
            elif t[i]>0:
                coins += t[i] - 1
                t[i] = 1
            else:
                coins+=1
                t[i] += 1

    less = 0
    great = 0
    for i in t:
        if i<0:
            less+=1
        else:
            great+=1    


    # print(coins)
    if less&1!=0:
        #odd
        coins+=2

    return print(coins)    

t = list(map(int, input().strip().split()))
solve(t)