#include <bits/stdc++.h>
using namespace std;
#define N 100005
typedef long long ll;
typedef unsigned long long ull;
ll n, a[N], s[2], ans = LONG_LONG_MIN, s1, s2;
int main() {
#ifndef ONLINE_JUDGE
  freopen("admin.in", "r", stdin);
  // freopen("admin.out", "w", stdout);
#endif
  scanf("%lld", &n);
  for (int i = 1; i <= n; i++)
    scanf("%lld", a + i);
  sort(a + 1, a + 1 + n);
  if (n == 1)
    return printf("%lld", abs(a[1])), 0;
  int l, r, now;
  s1 = s2 = LONG_LONG_MAX;
  if (a[1] < 0) {
    if (a[2] < 0) {
      s[0] = s[1] = 0;
      now = 0;
      for (int i = 1; i <= n; i++, now ^= 1)
        s[now] += a[i];
      s1 = abs(s[0]) - abs(s[1]);
    }
    if (a[n] >= 0) {
      s[0] = s[1] = 0;
      l = 1, r = n, now = 0;
      while (l <= r) {
        if (!(now & 1))
          s[0] += a[l++];
        else
          s[1] += a[r--];
        now ^= 1;
      }
      s2 = abs(s[0]) - abs(s[1]);
    }
  }
  if (s1 == s2 && s1 == LONG_LONG_MAX)
    s1 = s2 = 0;
  ans = max(ans, min(s1, s2));
  s1 = s2 = LONG_LONG_MAX;
  if (a[n] >= 0) {
    if (a[1] < 0) {
      s[0] = s[1] = 0;
      l = 1, r = n, now = 0;
      while (l <= r) {
        if (!(now & 1))
          s[0] += a[r--];
        else
          s[1] += a[l++];
        now ^= 1;
      }
      s1 = abs(s[0]) - abs(s[1]);
    }
    if (a[n - 1] >= 0) {
      s[0] = s[1] = 0;
      now = 0;
      for (int i = n; i >= 1; i--, now ^= 1)
        s[now] += a[i];
      s2 = abs(s[0]) - abs(s[1]);
    }
  }
  if (s1 == s2 && s1 == LONG_LONG_MAX)
    s1 = s2 = 0;
  ans = max(ans, min(s1, s2));
  printf("%lld", ans);
  return 0;
}