#include <bits/stdc++.h>
using namespace std;
int main(){
  int N;
  cin >> N;
  vector<int> c(N);
  for (int i = 0; i < N; i++){
    cin >> c[i];
  }
  int mx = max(*max_element(c.begin(), c.end()), 0);
  int mn = min(*min_element(c.begin(), c.end()), 0);
  cout << (mx - mn) * 2 << endl;
}