#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, neg = 0, sum = 0, mi = 1001;
  cin >> n;
  for (int i = 0; i < 2 * n - 1; i++) {
    int t;
    cin >> t;
    if (t < 0) neg++;
    if (abs(t) < mi) mi = abs(t);
    sum += abs(t);
  }
  if (n % 2 == 1 || neg % 2 == 0)
    cout << sum << endl;
  else
    cout << sum - 2 * mi << endl;
  return 0;
}
