#include<algorithm>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<fstream>
#include<iomanip>
#include<iostream>
#include<string>
using namespace std;
typedef long long LL;
const int INF=0x3f3f3f3f;
const int N=1e5+10;
const int eps=1e-5;
LL n,a[100010],ans;
int main()
{
    cin>>n;
    for(int i=1;i<=n;i++)
        cin>>a[i];
    sort(a+1,a+1+n);
    for(int i=1;i<=n;i++)
        ans+=abs(a[i]-a[n/2+1]);
    cout<<ans;
    return 0;
}