#include<iostream>
#include<vector>
#include<algorithm>

using namespace std;
using ll = long long;

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

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