#include<bits/stdc++.h> using namespace std; using ll = long long; int main(){ int n, k; cin >> n >> k; vector<int>V(n+9); V[0] = -1e9; for(int i = 1; i <= n; i++){ cin >> V[i]; } vector<int>S; for(int i = 1; i <= n; i++){ S.push_back((V[i]-1) - V[i - 1]); } ll s = 0; for(auto x : S)s += x + 1; sort(S.begin(),S.end(), greater<int>()); // k = n - k + 1; // k--; for(int i = 0; i < k; i++) s -= S[i]; cout << s << '\n'; }