#include <bits/stdc++.h>
using namespace std;
int a[1111111], b[1111111];
int main() {
  int j, i, n, m = 1111, k = 0, x = 0, y = 0;
  char c[55][55];
  cin >> n;
  for (i = 0; i < 2 * n - 1; i++) {
    cin >> x;
    k += abs(x);
    if (n % 2 == 0) {
      if (x < 0) y++;
      m = min(abs(x), m);
    }
  }
  if (n % 2 == 0 && y % 2) k = k - 2 * m;
  cout << k;
}
