#include<bits/stdc++.h> using namespace std; #define f first #define s second signed main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); int n, k; cin >> n >> k; int a[n]; for(int i = 0; i < n; ++i) cin >> a[i]; sort(a, a + n); int s = a[n - 1] - a[0] + 1; vector<pair<int, int>> b; for(int i = 1; i < n; ++i) b.push_back({a[i - 1] + 1, a[i] - 1}); sort(b.begin(), b.end(), [](const auto &a, const auto &b) { return (a.s - a.f) > (b.s - b.f); }); for(int i = 0; i < min(k - 1, n - 1); ++i) { if(b[i].f > b[i].s) break; s -= b[i].s - b[i].f + 1; } cout << s; }