#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
using ll =  long long ;
using P = pair<ll,ll> ;
const ll INF = 1e18;
const int MOD = 1000000007;

int main(){
    int n;
    cin >> n;
    vector<ll> a(n);
    rep(i,n) cin >> a[i];
    sort(a.begin(),a.end());
    ll ans = 0;
    if(n%2 == 0){
        rep(i,n){
            if(i < n/2) ans -= a[i];
            else ans += a[i];
        }
    }else{
        rep(i,n){
            if(i < n/2) ans -= a[i];
            else if(i > n/2) ans += a[i];
        }
    }
    cout << ans << endl;
    return 0;
}