#include <bits/stdc++.h>
namespace chtholly {
char buf[1 << 23], *p1 = buf, *p2 = buf;
inline int read() {
  int x = 0, f = 1;
  char c = getchar();
  for (; !isdigit(c); c = getchar()) f ^= c == '-';
  for (; isdigit(c); c = getchar()) x = (x << 3) + (x << 1) + (c ^ '0');
  return f ? x : -x;
}
template <typename mitsuha>
inline bool read(mitsuha &x) {
  x = 0;
  int f = 1;
  char c = getchar();
  for (; !isdigit(c) && ~c; c = getchar()) f ^= c == '-';
  if (!~c) return 0;
  for (; isdigit(c); c = getchar()) x = (x << 3) + (x << 1) + (c ^ '0');
  return x = f ? x : -x, 1;
}
template <typename mitsuha>
inline int write(mitsuha x) {
  if (!x) return 0 & putchar(48);
  if (x < 0) putchar('-'), x = -x;
  int bit[20], i, p = 0;
  for (; x; x /= 10) bit[++p] = x % 10;
  for (i = p; i; --i) putchar(bit[i] + 48);
  return 0;
}
inline char fuhao() {
  char c = getchar();
  for (; isspace(c); c = getchar())
    ;
  return c;
}
}  // namespace chtholly
using namespace chtholly;
using namespace std;
const int yuzu = 2e5;
typedef long long fuko[yuzu | 10];
struct node {
  long long a, id;
} p[yuzu | 10];
int main() {
  int i, n = read();
  long long s = 0, tmp = 0;
  for (i = 1; i <= n; ++i) p[i] = {read(), i}, s += p[i].a;
  if (n == 1) return printf("%lld\n", s) & 0;
  sort(p + 1, p + n + 1, [&](node a, node b) { return a.a < b.a; });
  auto ck = [&](int x) {
    for (int i = 1; i <= x; ++i)
      if (p[i].id & 1) return tmp;
    return tmp - p[x].a + p[x + 1].a;
  };
  long long zw = 9e9;
  for (i = 0; i <= n; ++i) {
    tmp += p[i].a;
    if (i % 3 == (4 - n % 3) % 3)
      zw = min(zw, n & 1 && n / 2 == i ? ck(i) : tmp);
  }
  printf("%lld\n", s - 2 * zw);
}
