#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)

using namespace std;
using ll = long long;

int main() {
    int n;
    cin >> n;
    
    ll pos = 0, neg = 0;
    rep(i, n) {
        ll c;
        cin >> c;
        if (c > 0) pos = max(pos, c);
        else neg = min(neg, c);
    }
    
    ll ans = (pos-neg)*2;
    cout << ans << '\n';
    
    return 0;
}