#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
#define RIDLs_code ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define fi1(x) for(int i=1;i<=x;++i)
#define fi0(x) for(int i=0;i<x;++i)
#define fj0(x) for(int j=0;j<x;++j)
#define fj1(x) for(int j=1;j<=x;++j)
#define For(elem, begin, end) for(int elem=begin;elem<end;++elem)
#define RFor(elem, begin, end) for(int elem=begin;elem>=end;--elem)
#define all(x) (x).begin(), (x).end()
#define pb push_back
const int MOD = 1e9+7;
const int INF = 0x3f3f3f3f;

void solve(){
    int n;
    cin>>n;
    vector<ll> a(n);
    deque<ll> aa;
    ll tmp;
    int op=1;
    ll x=0, y=0;
    fi0(n){
        cin>>a[i];
        // a.push_back
    }
    sort(all(a));
    fi0(n/2){
        // op*=-1;
        y+=a[i]*(-1LL*1);
    }
    For(i, n/2, n){
        x+=a[i];

    }
    cout<<x-y<<endl;

    return;
}
int main(){
	RIDLs_code
    int T=1;
    // cin>>T;
    while (T--) solve();
    return 0;
}