#include<bits/stdc++.h>
using namespace std;
#define el "\n"
#define pii pair<int,int>
#define fi first
#define se second
#define int long long
#define file(name) if(fopen(name".inp","r")){freopen(name".inp","r",stdin);freopen(name".out","w",stdout);}
const int N=1e5+10;
int n,k,a[N],ans;
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL); cout.tie(NULL);
cin>>n>>k;
ans=k;
for(int i=1;i<=n;i++)
cin>>a[i];
sort(a+1,a+1+n);
for(int i=1;i<n;i++)
a[i]=a[i+1]-a[i];
sort(a+1,a+n);
for(int i=1;i<=n-k;i++)
ans+=a[i];
cout<<ans;
return 0;
}
