N = int(input())
A = list(map(int,input().split()))
a,b = -A[0],-1000000000000000000000
for i in range(1,N):
  aa,bb = max(a,b - A[i],-A[i]),max(b,a + A[i])
  a,b = max(a,aa),max(b,bb)
print(max(a,b))