#include <bits/stdc++.h> using namespace std; #define int long long #define pb push_back #define fi first #define sc second const int mod = 1e+9; int dp[1000000]; queue<int>q; map<int,int>mp; signed main(){ int n, k; cin >> n >> k; vector<int>a(n); for(int i = 0; i < n; i++){ cin >>a[i]; } if(n <= k)cout << n << endl; else{ int bruh = 0; vector<int>v; for(int i = 0; i < n - 1; i++){ v.pb((a[i+1] - a[i]) - 1); } sort(v.rbegin(), v.rend()); for(int i = 0; i < k - 1; i++) { bruh += v[i]; } cout << (a[n-1] - a[0] + 1) - bruh << endl; } }