from collections import deque
N = int(input())
A = list(map(int,input().split()))
if N == 1:
    print(max(A)-min(A))
    exit()
B = []
for i in range(0,2*N-1,2):
    B.append(A[i]-A[i+1])

B = deque(B)
ans = 0
while B:
    if B[0] >= -B[-1]:
        ans += B.popleft()
    else:
        ans += -B.pop()
print(ans)