N=int(input())
A=list(map(int,input().split()))
left,right=-10**20,-10**20
for i in range(N):
    right_d=max(-A[i],right)
    right_d=max(left-A[i],right_d)
    left_d=max(right+A[i],left)
    right=right_d
    left=left_d
print(max(right,left))