#include <bits/stdc++.h>
using namespace std;
const int maxn = 230;
int a[maxn];
int main() {
  int n, i, sum, num, Mina = 1001;
  scanf("%d", &n);
  sum = num = 0;
  for (i = 1; i < n * 2; i++) {
    scanf("%d", &a[i]);
    a[i] > 0 ?: num++;
    sum += ((a[i]) > 0 ? (a[i]) : -(a[i]));
    if (Mina > ((a[i]) > 0 ? (a[i]) : -(a[i]))) {
      Mina = ((a[i]) > 0 ? (a[i]) : -(a[i]));
    }
  }
  if (n % 2 == 1) {
    printf("%d\n", sum);
  } else {
    if (num % 2 == 1)
      printf("%d\n", sum - 2 * Mina);
    else
      printf("%d\n", sum);
  }
  return 0;
}
