#include <bits/stdc++.h>
using namespace std;
const int inf = 19999999;
int pos = 0, neg = 0;
int total = 0, mini = inf;
int n;
int main() {
  scanf("%d", &n);
  int a;
  for (int i = 1; i < n * 2; i++) {
    scanf("%d", &a);
    if (a < 0) {
      neg++;
      a = -a;
    } else
      pos++;
    total += a;
    mini = min(a, mini);
  }
  if (n % 2 == 1)
    printf("%d\n", total);
  else if (neg % 2 == 0)
    printf("%d\n", total);
  else
    printf("%d\n", total - mini * 2);
  return 0;
}
