#include <bits/stdc++.h>
using namespace std;

void fast_io() {
	ios_base::sync_with_stdio(false);
	cin.tie(nullptr);
}

int main() {
	fast_io();
	int n;
	cin >> n;
	vector<long long> a(n);
	for (int i = 0; i < n; i++) {
		cin >> a[i];
	}
	long long INF = 1e18;
	vector<long long> dp = {0, -INF};
	for (int i = 0; i < n; i++) {
		vector<long long> dp_new = {-INF, -INF};
		dp_new[0] = max(dp[0], dp[1] + a[i]);
		dp_new[1] = max(dp[1], dp[0] - a[i]);
		dp = dp_new;
	}
	cout << max(dp[0], dp[1]) << endl;
}