#include<algorithm>
#include<complex>
#include<ctype.h>
#include<iomanip>
#include<iostream>
#include<fstream>
#include<map>
#include<math.h>
#include<numeric>
#include<queue>
#include<set>
#include<stack>
#include<stdio.h>
#include<string>
#include<string>
#include<vector>

using namespace std;
typedef long long ll;

#define FOR(i,a,b) for(ll i=(a);i<(b);++i)
#define ALL(v) (v).begin(), (v).end()
#define p(s) cout<<(s)<<endl
#define p2(s, t) cout << (s) << " " << (t) << endl
#define br() p("")
#define pn(s) cout << (#s) << " " << (s) << endl
#define p_yes() p("Yes")
#define p_no() p("No")

const ll mod = 1e9 + 7;
const ll inf = 1e18;

template < typename T >
void vprint(T &V){
	for(auto v : V){
    	cout << v << " ";
	}
	cout << endl;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);

    // input
    ll N, K;
    cin >> N >> K;

    map<ll, ll> mp;
    FOR(i, 0, N){
        ll a;
        cin >> a;
        mp[a] = 1;
    }

    vector<ll> A;
    for(auto p : mp){
        A.push_back(p.first);
    }
    sort(ALL(A));

    ll L = A.size();

    if(L<=K){
        p(0);
        return 0;
    }

    // diff
    vector<ll> D;
    FOR(i, 1, L){
        ll diff = A[i] - A[i-1];
        D.push_back(diff);
    }
    sort(ALL(D));

    ll num = L - K; // あと何回マージが必要か
    ll sum = 0;
    FOR(i, 0, num){
        sum += D[i];
    }

    p(sum);
    
    return 0;
}