N = int(input())
A = list(map(int,input().split()))
D = [A[i + 1] - A[i] for i in range(N - 1)]
ans = max(D)
if ans < 0:
  print(ans)
  exit()
a,b = -A[0],0
for i in range(2,N):
  a,b = max(a,b - A[i]),max(b,a + A[i])
print(max(a,b))