N = int(input())
A = list(map(int,input().split()))
l = 0
r = 2*N-1
ans = 0
while l < r:
    if A[l]-A[l+1] > A[r]-A[r-1]:
        ans += A[l]-A[l+1]
        l += 2
    else:
        ans += A[r]-A[r-1]
        r -= 2
print(ans)