#include <bits/stdc++.h>
using namespace std;
int n, m, a;
int main() {
  while (scanf(" %d", &n) == 1) {
    int sum = 0, cnt = 0, minn = 1003;
    m = 2 * n - 1;
    while (m--) {
      scanf(" %d", &a);
      if (a < 0) {
        cnt++;
        a = -a;
      }
      sum += a;
      minn = min(minn, a);
    }
    if (n & 1 || !(cnt & 1))
      printf("%d\n", sum);
    else
      printf("%d\n", sum - 2 * minn);
  }
  return 0;
}
