#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i = 0; i < n; i++)
#define rep2(i, x, n) for(int i = x; i <= n; i++)
#define rep3(i, x, n) for(int i = x; i >= n; i--)
#define each(e, v) for(auto &e: v)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) (int)x.size()
using ll = long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
const int MOD = 1000000007;
//const int MOD = 998244353;
const int inf = (1<<30)-1;
const ll INF = (1LL<<60)-1;
template<typename T> bool chmax(T &x, const T &y) {return (x < y)? (x = y, true) : false;};
template<typename T> bool chmin(T &x, const T &y) {return (x > y)? (x = y, true) : false;};

struct io_setup{
    io_setup(){
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
        cout << fixed << setprecision(15);
    }
} io_setup;

int main(){
    int N; cin >> N;

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

    sort(rall(c));
    ll A = 0, B = 0;
    rep(i, N){
        if(i&1) B += c[i];
        else A += c[i];
    }

    ll P = INF, Q = INF;
    if(A >= 0 && B >= 0) chmin(P, A-B);
    if(N%2 == 0) swap(A, B);
    if(A <= 0 && B <= 0) chmin(Q, B-A);

    A = 0, B = 0;
    int n = (N+1)/2, m = N-m;
    rep(i, n) A += c[i];
    rep(i, m) B += c[n+i];
    if(A >= 0 && B <= 0) chmin(P, A+B);

    A = 0, B = 0, reverse(all(c));
    rep(i, n) A += c[i];
    rep(i, m) B += c[n+i];
    if(A <= 0 && B >= 0) chmin(Q, -A-B);

    cout << max(P, Q) << '\n';
}