/*
TASK:ots
LANG:C++
*/
#include<iostream.h>
long a[1000101],b[1000101];
void sort(long l,long r)
{ long i,j,x,y;
  i=l;
  j=r;
  x=a[(l+r)/2];
  do
  { while (a[i]<x) i++;
    while (a[j]>x) j--;
    if (i<=j)
    { y=a[i];
      a[i]=a[j];
      a[j]=y;
      i++;
      j--;
    }
  } while (i<=j);
  if (l<j) sort(l,j);
  if (i<r) sort(i,r);
}
int main()
{ long k,k1,n,i;
  unsigned long long br=0;
  cin>>n;
  for(i=1;i<=n;i++) cin>>a[i];
  sort(1,n);
  for(i=2;i<=n;i++)
  { k=a[i]-a[i-1];
    if (i<n) k1=a[i+1]-a[i];
    if (i==n)
    { if (b[i-1]!=a[i]) br+=k;
      b[i]=a[i-1];
    }
    else
    { if (k<k1)
      { if (b[i-1]!=a[i]) br+=k;
	b[i]=a[i-1];
      }
      else
      { br+=k1;
	b[i]=a[i+1];
      }
    }
  }
  if (b[2]!=a[1]) br+=a[1];
  cout<<br<<endl;
return 0;
}
