#include <bits/stdc++.h>
using namespace std;
#define int long long
const int mxN = 1e5 + 7;
int n, k, arr[mxN], dsu[mxN];
int find(int x) {
return (dsu[x] < 0 ? x : dsu[x] = find(dsu[x]));
}
bool unite(int x, int y) {
x = find(x), y = find(y);
if (x == y) {
return false;
}
if (dsu[x] > dsu[y]) {
swap(x, y);
}
dsu[x] += dsu[y];
dsu[y] = x;
return true;
}
int32_t main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> k;
memset(dsu, -1, sizeof(dsu));
for (int i = 0; i < n; ++i) {
cin >> arr[i];
}
sort(arr, arr + n);
vector<pair<int,pair<int,int>>> difs;
for (int i = 0; i < n - 1; ++i) {
difs.push_back({arr[i + 1] - arr[i], {i + 1, i}});
}
sort(difs.begin(), difs.end());
int ans = n, cnt = n;
for (auto p : difs) {
int dif = p.first, u = p.second.first, v = p.second.second;
if (unite(u, v) && cnt > k) {
//cout << dif << ' ' << u << ' ' << v << "\n";
ans += dif - 1;
--cnt;
}
}
cout << ans << "\n";
}
