#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int main() {
	std::ios_base::sync_with_stdio(false);
	std::cin.tie(nullptr);
	int N;
	cin >> N;
	vector<ll> neg, pos;
	for(int i = 0; i < N; i++) {
		int a;
		cin >> a;
		if(a < 0) neg.push_back(a);
		else pos.push_back(a);
	}
	ll ans = 0;
	if(!neg.empty()) ans += abs(neg.front())*2;
	if(!pos.empty()) ans += abs(pos.back())*2;
	cout << ans << endl;
}