#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  while (cin >> n) {
    int sum = 0;
    int od = 10000;
    int fu = 0;
    int x;
    for (int i = 0; i < 2 * n - 1; i++) {
      scanf("%d", &x);
      fu += x < 0;
      x = max(x, -x);
      sum += x;
      od = min(od, x);
    }
    if (!(fu & 1) || (n & 1) || !(fu & 1))
      cout << sum << endl;
    else
      cout << sum - 2 * od << endl;
  }
  return 0;
}
