import sys
input=lambda:sys.stdin.readline().rstrip()
N=int(input())
A=sorted(list(map(int,input().split())))
if N==1:
	print(abs(A[0]))
elif sum(A)>0:
	print(abs(sum(A[N-1::-2]))-abs(sum(A[N-2::-2])))
else:
	print(abs(sum(A[::2]))-abs(sum(A[1::2])))