#include <bits/stdc++.h>
using namespace std;
const int MAXN = 210;
int a[MAXN];
int main() {
  int n;
  cin >> n;
  int m = 0, sum = 0;
  for (int i = 1; i <= 2 * n - 1; i++) {
    cin >> a[i];
    if (a[i] < 0) m++, a[i] *= -1;
    sum += a[i];
  }
  int min = 10000;
  for (int i = 1; i <= 2 * n - 1; i++)
    if (a[i] < min) min = a[i];
  if (n % 2 == 0 && m % 2) sum -= 2 * min;
  cout << sum << endl;
  return 0;
}
