def solve() :
    n=int(input())
    if n<2 or n>100000 :
        print("waaaaaa")
    a = list(map(int, input().split()))
    if len(a) != n : 
        print("hogeeeeeee")
    for i in a : 
        if abs(i) >1000000000 :
            print("guaaaaaaa")
    a.sort()
    x=0
    y=0
    for i in range(n) :
        if i%2 == 0 : x+=a[i]
        else : y+=a[i]
    print(abs(abs(x)-abs(y)))
solve()