#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ul = unsigned long;

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

	int n;
	cin >> n;

	vector<ll> a(n * 2);
	ll sumall{ 0 };
	for (auto&& ia : a)
	{
		cin >> ia;
		sumall += ia;
	}

	ll res{ 0 };
	if (n == 1)
		res = abs(a[0] - a[1]);
	else
	{
		vector<ll> suml(n + 1, 0), sumr(n + 1, 0);
		for (int i = 0; i < n; ++i)
		{
			suml[i + 1] = suml[i] + a[i * 2];
			sumr[n - 1 - i] = sumr[n - i] + a[n * 2 - 1 - i * 2];
		}

		for (int i = 0; i < n + 1; ++i)
			res = max(res, (suml[i] + sumr[i]) * 2 - sumall);
	}
	cout << res << "\n";

	return 0;
}