#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;
    
    vector<ll> a(n);
    rep(i, n) cin >> a[i];
    
    vector<ll> pos, neg;
    ll s = 0;
    for (ll x : a) {
        if (x >= 0) pos.push_back(x);
        else {
            neg.push_back(-x);
            s += -x;
        }
    }
    sort(neg.begin(), neg.end(), greater<>());

    ll ans = 1e18;
    if (!pos.size()) {
        ll mx1 = neg[0], mx2 = neg[1];
        ans = 2*s-(mx1+mx2);
    }
    else {
        ll pmx = *max_element(pos.begin(), pos.end());
        if (!neg.size()) {
            ll pmn = *min_element(pos.begin(), pos.end());
            ans = min(ans, pmx-pmn);
            cout << ans << '\n';
            return 0;
        }
        
        ll mx1 = neg[0];
        ans = min(ans, 2*s-mx1+pmx);
        if (neg.size() >= 2) {
            ll mx2 = neg[1];
            ans = min(ans, 2*s-(mx1+mx2) + 2*pmx);
        }
    }
    
    cout << ans << '\n';
    
    return 0;
}