#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
constexpr long long mod = 998244353;
const long long INF = mod * mod;
const double eps = 1e-12;
const double pi = acosl(-1.0);
long long mod_pow(long long x, long long n, long long m = mod) {
  if (n < 0) {
    long long res = mod_pow(x, -n, m);
    return mod_pow(res, m - 2, m);
  }
  if (abs(x) >= m) x %= m;
  if (x < 0) x += m;
  long long res = 1;
  while (n) {
    if (n & 1) res = res * x % m;
    x = x * x % m;
    n >>= 1;
  }
  return res;
}
struct modint {
  long long n;
  modint() : n(0) { ; }
  modint(long long m) : n(m) {
    if (n >= mod)
      n %= mod;
    else if (n < 0)
      n = (n % mod + mod) % mod;
  }
  operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
modint operator+=(modint& a, modint b) {
  a.n += b.n;
  if (a.n >= mod) a.n -= mod;
  return a;
}
modint operator-=(modint& a, modint b) {
  a.n -= b.n;
  if (a.n < 0) a.n += mod;
  return a;
}
modint operator*=(modint& a, modint b) {
  a.n = ((long long)a.n * b.n) % mod;
  return a;
}
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, long long n) {
  if (n == 0) return modint(1);
  modint res = (a * a) ^ (n / 2);
  if (n % 2) res = res * a;
  return res;
}
long long inv(long long a, long long p) {
  return (a == 1 ? 1 : (1 - p * inv(p % a, a)) / a + p);
}
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }
modint operator/=(modint& a, modint b) {
  a = a / b;
  return a;
}
const int max_n = 1 << 2;
modint fact[max_n], factinv[max_n];
void init_f() {
  fact[0] = modint(1);
  for (int i = 0; i < max_n - 1; i++) {
    fact[i + 1] = fact[i] * modint(i + 1);
  }
  factinv[max_n - 1] = modint(1) / fact[max_n - 1];
  for (int i = max_n - 2; i >= 0; i--) {
    factinv[i] = factinv[i + 1] * modint(i + 1);
  }
}
modint comb(int a, int b) {
  if (a < 0 || b < 0 || a < b) return 0;
  return fact[a] * factinv[b] * factinv[a - b];
}
modint combP(int a, int b) {
  if (a < 0 || b < 0 || a < b) return 0;
  return fact[a] * factinv[a - b];
}
vector<string> s[11];
void expr() {
  s[1] = {"1"};
  for (int i = 2; i <= 10; i++) {
    for (int j = 1; j < i; j++) {
      for (string t : s[j])
        for (string u : s[i - j]) {
          string ad = t + u;
          for (int k = 0; k < ad.size(); k++) ad[k] = '0' + '1' - ad[k];
          s[i].push_back(ad);
        }
    }
    sort((s[i]).begin(), (s[i]).end());
    s[i].erase(unique((s[i]).begin(), (s[i]).end()), s[i].end());
  }
  for (int i = 1; i <= 8; i++) {
    cout << i << " start "
         << "\n";
    for (string t : s[i]) cout << t << "\n";
  }
}
void solve() {
  int n;
  cin >> n;
  vector<long long> a(n);
  for (int i = 0; i < n; i++) cin >> a[i];
  if (n == 1) {
    cout << a[0] << "\n";
    return;
  }
  if (n % 2 == 0) {
    sort((a).begin(), (a).end());
    vector<long long> ra(n + 1);
    for (int i = 0; i < n; i++) ra[i + 1] = ra[i] + a[i];
    int c = (n / 2) % 3;
    c = (c + 2) % 3;
    long long ans = -INF;
    for (int x = c; x <= n; x += 3) {
      long long sum = ra[n] - ra[n - x] - (ra[n - x]);
      ans = max(ans, sum);
    }
    cout << ans << "\n";
  } else {
    vector<pair<long long, long long> > v(n);
    for (int i = 0; i < n; i++) v[i] = {a[i], i};
    sort((v).begin(), (v).end());
    vector<long long> ra(n + 1);
    for (int i = 0; i < n; i++) {
      ra[i + 1] = ra[i] + v[i].first;
    }
    int c = (n + 1) / 2;
    c %= 3;
    long long ans = -INF;
    for (int x = c; x <= n; x += 3) {
      if (x == (n + 1) / 2) {
        bool valid = false;
        for (int j = 0; j < x; j++) {
          if (v[n - 1 - j].second % 2) valid = true;
        }
        if (valid) {
          long long sum = ra[n] - ra[n - x] - (ra[n - x]);
          ans = max(ans, sum);
        } else {
          long long sum = ra[n] - ra[n - x] - (ra[n - x]);
          sum -= 2 * v[n / 2].first;
          sum += 2 * v[n / 2 - 1].first;
          ans = max(ans, sum);
        }
      } else {
        long long sum = ra[n] - ra[n - x] - (ra[n - x]);
        ans = max(ans, sum);
      }
    }
    cout << ans << "\n";
  }
}
signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  solve();
  return 0;
}
