#include <bits/stdc++.h>
using namespace std;
long n, minn, s, i, k, a[500] = {};
int main() {
  cin >> n;
  minn = 10000000;
  for (i = 1; i < 2 * n; i++) {
    cin >> a[i];
    if (a[i] < 0) {
      k++;
      a[i] = -a[i];
    }
    s += a[i];
    minn = min(minn, a[i]);
  }
  if ((n % 2 == 1) || (k % 2 == 0))
    cout << s << endl;
  else
    cout << s - 2 * minn << endl;
  return 0;
}
