import sys
input=sys.stdin.readline
def I(): return int(input())
def MI(): return map(int, input().split())
def LI(): return list(map(int, input().split()))

def main():
    mod=10**9+7
    N=I()
    A=LI()
    l=0
    r=2*N-1
    
    ans=0
    for i in range(N):
        a=A[l]-A[l+1]
        b=A[r]-A[r-1]
        if a>b:
            ans+=a
            l+=2
        else:
            ans+=b
            r-=2
            
    print(ans)
    
    


main()