#include <iostream>
#include <cstdint>
#include <vector>
#include <array>

using namespace std;

int main()
{
	cin.tie(nullptr);
	ios::sync_with_stdio(false);

	uint32_t N, i;
	cin >> N;
	vector<int32_t> A(N);
	for (i = 0; i != N; ++i) cin >> A[i];

	if (N == 1)
	{
		cout << A[0] << '\n';
		return 0;
	}

	array<int64_t, 2> cur = { -A[0] + A[1], max(-A[0], -A[1]) }, prev = { INT64_MIN, INT64_MIN };
	for (i = 2; i != N; ++i)
	{
		prev = cur;

		if (cur[0] < prev[1] + A[i]) cur[0] = prev[1] + A[i];
		if (cur[1] < prev[0] - A[i]) cur[1] = prev[0] - A[i];
		if (cur[1] < -A[i]) cur[1] = -A[i];
	}

	cout << max(cur[0], cur[1]) << '\n';
	return 0;
}