mod = 1000000007
eps = 10**-9


def main():
    import sys
    input = sys.stdin.readline

    N = int(input())
    C = list(map(int, input().split()))
    C.sort()
    A = B = 0
    for i, c in enumerate(C):
        if i&1:
            B += c
        else:
            A += c
    if N&1:
        print(abs(A) - abs(B))
    else:
        print(abs(abs(A) - abs(B)))


if __name__ == '__main__':
    main()