#include<bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (int)(n); i++)
using namespace std;
typedef long long ll;   
ll LINF = (1LL << 61) - 1;
int INF = (1LL << 30) - 1;
int MOD = 1e9+7;
vector<int> V;
ll getAbs(ll mid){
    ll sum = 0;
    for(auto i:V){
        sum += abs(i - mid);
    }
    return sum;
}
main(){
    int N;
    cin >> N;
    V.resize(N);
    rep(i,N){
        cin >> V[i];
    }
    sort(V.begin(), V.end());
    cout << getAbs(V[N/2]) << endl;
}