#include <bits/stdc++.h>
int main() {
  int m, n, i, min = 10000, sum = 0, a[202], d = 0;
  scanf("%d", &n);
  m = 2 * n - 1;
  for (i = 0; i < m; i++) {
    scanf("%d", &a[i]);
    if (a[i] < 0) {
      d++;
      a[i] = -a[i];
    }
    if (a[i] < min) min = a[i];
    sum += a[i];
  }
  if (n % 2 != 0)
    printf("%d\n", sum);
  else {
    if (d % 2 != 0)
      printf("%d\n", sum - min * 2);
    else
      printf("%d\n", sum);
  }
  return 0;
}
