#include"bits/stdc++.h"
#include"atcoder/all"
#define chmin(x,y) (x) = min((x),(y))
#define chmax(x,y) (x) = max((x),(y))
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define vec vector
#define all(a) a.begin(), a.end()
#define pb push_back 

using namespace std;
using namespace atcoder;
using ll = long long;
using ld = long double;
const ll mod = 998244353;
using mint = modint998244353;
using Graph = vector<vector<pair<int,ll>>>;
const vector<int> dx = {1,0,-1,0}, dy = {0,1,0,-1};

int main(){
	// input
	int N;
	cin >> N;
	ll L = 0, R = 0;
	rep(i,N){
		ll x;
		cin >> x;
		if(x < 0) chmin(L,x);
		else if(x > 0) chmax(R,x);
	}
	
	cout << 2 * (R - L) << endl;
}