// #pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#include <bits/stdc++.h>
using namespace std;
#define IMAX 2147483647
#define LMAX 9223372036854775807
#define IOS ios_base::sync_with_stdio(0);cin.tie(0);
#define fou(i,a,n) for(int i=a;i<n;i++)
#define fod(i,a,n) for(int i=n-1;i>=a;i--)
#define rep(n) fou(_,0,n)
#define tra(a,x) for(auto& a : x)
#define elif(c) else if(c)
#define VI vector<int>
#define VD vector<double>
#define VC vector<char>
#define VS vector<string>
#define VVI vector<VI>
#define VVD vector<VD>
#define VVC vector<VC>
#define VVS vector<VS>
#define PII pair<int,int>
#define PIII pair<int,PII>
#define VPII vector<PII>
#define VPIII vector<PIII>
#define emb emplace_back
#define pub push_back
#define pob pop_back
#define mp make_pair
#define mp3(a,b,c) mp(a,mp(b,c))
#define fi first
#define se second
#define th se.se
#define si(vec) ((int)(vec).size())
#define all(vec) vec.begin(),vec.end()
#define lla(vec) vec.rbegin(),vec.rend()
#define range(vec,x,y) vec.begin()+x,vec.begin()+y
#define sortup(vec) sort(all(vec))
#define sortdown(vec) sort(lla(vec))
#define rotateleft(vec,n) rotate(a.begin(),a.begin()+n,a.end())
#define rotateright(vec,n) rotate(a.rbegin(),a.rbegin()+n,a.rend())
#define eraseif(vec,condition_VAR) vec.erase(remove_if(all(vec),[&](auto VAR){return condition_VAR;}),vec.end())
#define countif(vec,condition_VAR) count_if(all(vec),[&](auto VAR){return condition_VAR;})
#define replaceif(vec,condition_VAR,n) replace_if(all(vec),[&](auto VAR){return condition_VAR;},n)
#define erase_unique(vec) vec.erase(unique(all(vec)),vec.end())
#define calcvec(vec,calc_VAR) for_each(all(vec),[&](auto&VAR){VAR=calc_VAR;});
#define calc2vec(vec1,op,vec2) {rep(1){int s=min(si(vec1),si(vec2));fou(i,0,s)vec1[i]=vec1[i] op vec2[i];}}
template<class C>void mini(C &a,C b){a=min(a,b);}
template<class C>void maxi(C &a,C b){a=max(a,b);}
#define in(T,...) T __VA_ARGS__;_cin(__VA_ARGS__);
#define out(...) _cout(__VA_ARGS__);
void _cin(){}template<class Head,class...Tail>void _cin(Head&head,Tail&&...tail){cin>>head;_cin(forward<Tail>(tail)...);}
template<class Head>void _cout(Head head){cout<<head<<endl;}template<class Head,class...Tail>void _cout(Head head,Tail...tail){cout<<head<<" ";_cout(forward<Tail>(tail)...);}
template<class C>void outvec(vector<C> vec){int vecsize=si(vec);fou(i,0,vecsize-1)cout<<vec[i]<<" ";out(vec[vecsize-1]);}
template<class C> C gcd(C a,C b){if(a&&b)return gcd(min(a,b),max(a,b)%min(a,b));else return a;}
template<class C> C lcm(C a,C b){return a/gcd(a,b)*b;}
template<class C>int binarysearch(vector<C> vec,C n,char c){int left=-1;int right=si(vec);bool outleft=(c=='d'||c=='U');int getmin=(c=='u'||c=='d')?1:-1;while(right-left>1){int mid=left+(right-left)/2;bool OK=vec[mid]*getmin>=n*getmin;if(outleft==OK) left=mid;else right=mid;}return outleft?left:right;}


#define int int64_t
// #define double long double


// map,makepair


signed main(){
  IOS;

  in(int,n);
  VI a(n);
  fou(i,0,n) cin>>a[i];

  sortup(a);
  fou(i,0,n/2) {
    if(a[i*2]<0&&a[i*2+1]<0){
      a[i*2]*=-1;
      a[i*2+1]*=-1;
    }
    elif(a[i*2]<0&&a[i*2+1]>=0){
      if(a[i*2]+a[i*2+1]<0){
        a[i*2]*=-1;
        a[i*2+1]*=-1;
      }
      break;
    }
    else break;
  }
  int ans=0;
  fou(i,0,n) ans+=a[i];
  out(ans);
}

Measured memory_bytes: 1024