#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
const int nx = 1e5+5;
int n, k;
vector<int> mn;
vector<pii> adj;
int main()
{
cin.tie(NULL)->sync_with_stdio(false);
cin >> n >> k;
for(int i=1;i<=n;i++)
{
int t; cin >> t;
adj.push_back({t, 0});
adj.push_back({t + 1, 1});
}
// 0 front, 1 back
for(int i=0;i<adj.size()-1;i++)
{
auto [v, pos] = adj[i];
auto [nv, next] = adj[i + 1];
if(pos == 1 && next == 0) mn.push_back(nv - v);
}
sort(mn.begin(), mn.end());
int res = n;
for(int i=0;i<n-k;i++) res += mn[i];
cout << res ;
return 0;
}
