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

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N; cin >> N;
    int low = 0,high = 0;
    while(N--){
        int c; cin >> c;
        low = min(low,c);
        high = max(high,c);
    }
    low = abs(low);
    cout << low+low+high+high << endl;
}