#include <bits/stdc++.h>
using namespace std;
const int size = 508;
int num[size];
int Abs(int x) { return x > 0 ? x : -x; }
int main() {
  int n, sum, m, i, x, L, R, c, t, v, up;
  cin >> n;
  sum = m = 0;
  up = 1000000;
  for (i = 1; i <= 2 * n - 1; i++) {
    cin >> num[i];
    if (num[i] < 0) m++;
    sum += Abs(num[i]);
    if (up > Abs(num[i])) up = Abs(num[i]);
  }
  if (n & 1) {
    cout << sum << endl;
    return 0;
  }
  if (m & 1) {
    cout << sum - 2 * up << endl;
  } else
    cout << sum << endl;
  return 0;
}
