#include "bits/stdc++.h"
using namespace std;
#define ll long long
#define endl '\n'
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define rep2(i,a,b) for(int i=int(a);i<int(b);i++)
#define pb emplace_back
#define all(x) (x).begin(),(x).end()
int mod=1e9+7;
int mod2=998244353;
const int INF=1e9;

signed main(){
	ll n;
  cin>>n;
  ll sum=0;
  ll mina=1e18;
  ll tmp=0;
  ll a;
  rep(i,n){
    cin>>a;
    if(a<0)tmp++;
    sum+=abs(a);
    mina=min(mina,abs(a));
  }
  if(tmp%2==0)cout<<sum<<endl;
  else cout<<sum-mina*2<<endl;

}

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