/*
TASK:ots
LANG:C++
*/
#include <cstdio>
#include <cstdlib>
using namespace std;
long v[1000000]={0};
int cmp(const void*a,const void*b)
{
 long*p=(long*)a;
 long*q=(long*)b;
 if(*p>*q)return 1;
 if(*p<*q)return -1;
 return 0;
}
int main()
{
 long a,N,i,how=0;
// cin>>N;
 scanf("%d",&N);
 for(i=0;i<N;i++)//cin>>v[i];
        scanf("%d",&v[i]);
 qsort(v,N,sizeof(long),cmp);
 for(i=0;i<N-1;i++)
        {
         v[i]=v[i+1]-v[i];
        }
 qsort(v,N,sizeof(long),cmp);
 for(i=0;i<=N/2;i++)how+=v[i];
//cout<<how<<endl;
 printf("%d\n",how);

return 0;
}


