#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define OPT ios_base::sync_with_stdio(0); \
cin.tie(0); \
cout.tie(0)
#define pii pair<int,int>
#define pll pair<ll,ll>
#define endl "\n"
#define all(v) v.begin(), v.end()
#define mpr make_pair
#define pb push_back
#define ts to_string
#define fi first
#define se second
#define inf 0x3F3F3F3F
#define bpc __builtin_popcount
#define print(v) for(int i = 0; i < v.size(); i++) \
cout << v[i] << " "; \
cout<<endl;
int main()
{
int n, k;
cin >> n >> k;
vector<int> v(n, 0);
for (int i = 0; i < n; i++) cin >> v[i];
sort(all(v));
vector<int> a;
for (int i = 1; i < n; i++)
{
a.pb(v[i] - v[i - 1]);
}
sort(all(a));
int x = n - k;
int res = 0;
for (int i = 0; i < x; i++)
{
res += a[i];
}
cout << res + k << endl;
}
///1 3 6 10
