#include <bits/stdc++.h>
#define int long long
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define sc second
#define endl "\n"
#define pii pair<int,int>
using namespace std;
const int MAXN = 1e5+5;
const int mod7 = 1e9+7;
const long long inf = 1e18;
signed main()
{
ios_base::sync_with_stdio(false),cin.tie(0), cout.tie(0);
int tt=1;
//cin >> tt;
while(tt--)
{
int n, k;
cin >> n >> k;
vector<int> niz(n);
for(int i=0; i<n; i++)cin >> niz[i];
sort(all(niz));
vector<int> razlike;
for(int i=1; i<n; i++)razlike.pb(niz[i] - niz[i-1]);
sort(all(razlike));
int rez = 0;
for(int i=0; i<n-k; i++)rez+= razlike[i];
rez+=k;
cout << rez << endl;
}
}
