#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<ll,ll> P;
#define REP(i,n) for(ll i=0;i<ll(n);i++)











int main(void){
	cin.tie(nullptr);  ios_base::sync_with_stdio(false);
	ll i,j;


	ll N;
	cin >> N;
	vector<ll> c(N);
	REP(i,N) cin >> c[i];

	sort(c.begin(),c.end());

	if(c[0]>=0) cout << 2*c[N-1] << endl;
	else if(c[N-1]>=0) cout << 2*(c[N-1]-c[0]) << endl;
	else cout << -2*c[0] << endl;









	return 0;
}