n = int(input())
a = list(map(int,input().split()))

dp0 = [-10 ** 18] * n
dp1 = [-10 ** 18] * n

for i in range(n):
	dp1[i] = max(dp1[i], - a[i])
	if i-1 >= 0:
		dp0[i] = max(dp0[i], dp1[i-1] + a[i])
		dp1[i] = max(dp1[i], dp0[i-1] - a[i])
		dp0[i] = max(dp0[i], dp0[i-1])
		dp1[i] = max(dp1[i], dp1[i-1])

print(max(dp0[n-1], dp1[n-1]))