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

#define rep(i, n) for (int i = 0; i < (int)n; i++)
using ll = long long int;

int main() {
  int n;
  cin >> n;
  vector<int> c(n);
  rep(i, n) cin >> c[i];
  int maxv = *max_element(c.begin(), c.end());
  int minv = *min_element(c.begin(), c.end());
  if ((maxv > 0 && minv > 0) || (maxv< 0 && minv < 0))
    cout << max(abs(maxv), abs(minv)) * 2 << endl;
  else
    cout << abs(maxv)*2 + abs(minv)*2 << endl;
  return 0;
}