#include<bits/stdc++.h>
#define endl "\n"
#define ll long long
#define pii pair<int,int>
using namespace std;

int main() {
	int n; cin >> n;
	vector<int>arr(n + 1,0);
	vector<int>d(n + 1, 0);
	int z = 0, f = 0;
	for (int i = 1; i <= n; i++) {
		cin >> arr[i];
		d[i] = arr[i] - arr[i - 1];
		if (d[i] > 0)z += d[i];
		else f += abs(d[i]);
	}
	cout << max(z, f);

	return 0;
}