from collections import deque
N = int(input())
A = tuple(map(int, input().split()))

ans = 0
head = 0
tail = 2*N-1
while tail > head:
    x = A[head] - A[head+1]
    y = A[tail] - A[tail-1]
    if x > y:
        ans += x
        head += 2
    else:
        ans += y
        tail -= 2
print(ans)