#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    int n; cin >> n;
    int l = 0, r = 0;
    for (int i = 0; i < n; i++) {
        int c; cin >> c;
        if (c >= 0) r = max(r, c);
        else l = min(l, c);
    }
    cout << 2 * (r - l) << "\n";
    return 0;
}