# -*- coding: utf-8 -*-
n = int(input())
arr = [int(input()) for i in range(n)]
heap1 = []
heap2 = []
arr.sort(reverse=True)
for element in arr:
    if sum(heap1) >= sum(heap2): heap2.append(element)
    else: heap1.append(element)
result = abs(sum(heap1) - sum(heap2))
print(result)