#include<bits/stdc++.h>
using namespace std;
#define int long long
#define YES cout << "YES";
#define nl cout << endl;
#define NO cout << "NO";
#define all(x) x.begin(), x.end()
#define allr(x) x.rbegin(), x.rend()
#define pb push_back
#define ppb pop_back
#define mp make_pair
#define ff first
#define ss second
#define st string
#define fr(i, x, y) for (int i = x; i < y; i++)
#define FAST ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define MAX 1e18
#define MIN -1e18
const int MOD = 1e9 + 7;
const int N = 3e5 + 100;
void solve() {
int n, k ;cin>>n>>k;
vector<int> diff, v(n);
for(int i = 0;i<n;++i){
cin>>v[i];
}
sort(all(v));
for(int i= 0;i<n-1;++i){
diff.pb(v[i+1] - v[i]);
}
sort(all(diff));
int ans = k;
for(int i = 0;i<n - k;++i){
ans+=diff[i];
}
cout<<ans;
}
int32_t main() {
FAST
int t = 1;
// cin >> t;
while (t--) {
solve();
cout << endl;
}
}
