#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
int main()
{
  int n;
  cin >> n;
  vector<int>c(n);
  for(int i=0;i<n;i++)cin >> c[i];
  int left=1e9,right=-1e9;
  for(int i=0;i<n;i++)left=min(left,c[i]);
  for(int i=0;i<n;i++)right=max(right,c[i]);

  if(left<=0 && right>=0)cout << (left*-1)*2+right*2 << endl;
  else if(left<=0 && right<=0)cout << (left*-1)*2 << endl;
  else cout << right*2 << endl;
}