#include <bits/stdc++.h>
using namespace std;
int a[1000000], l[1000000], r[1000000];
int main() {
  int n;
  cin >> n;
  int minn = 10000000;
  int kol = 0;
  int ans = 0;
  int m = 2 * n - 1;
  for (int i = 0; i < m; i++) {
    cin >> a[i];
    if (a[i] < 0) {
      kol++;
      a[i] = -a[i];
    }
    ans += a[i];
    if (a[i] < minn) minn = a[i];
  }
  if (n % 2 == 1)
    cout << ans << endl;
  else {
    if (kol % 2 == 0)
      cout << ans << endl;
    else
      cout << ans - 2 * minn << endl;
  }
}
