#include<bits/stdc++.h>
using namespace std;
const int N = 1e5+1;
int a[N],b[N],gap[N];
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
int n;
long long k;cin>>n>>k;
for(int i = 0; i < n; ++i)cin>>a[i];
sort(a, a + n);
int m = 0;
b[m++] = a[0];
for(int i = 1; i < n; ++i){
if(a[i] != a[i - 1]){
b[m++] = a[i];
}
}
if(k >= m){
cout<<m<<'\n';
return 0;
}
long long res = m;
for(int i = 0; i < m - 1; ++i)gap[i] = b[i + 1] -(b[i] + 1);
sort(gap, gap + m - 1);
int need = m - k;
for(int i = 0; i < need; ++i)res += gap[i];
cout<<res<<'\n';
return 0;
}
