#include <bits/stdc++.h>
using namespace std;
#define pii pair<int, int>
#define F first
#define S second
const int maxn = 1e5 + 5;
int n, k;
int arr[maxn];
bool fg[maxn];
int s[maxn];
int pa[maxn];
int res;
bool comp(const int &a, const int &b){
return arr[a+1] - arr[a] < arr[b+1] - arr[b];
}
int findset(int u){
if(pa[u] == u) return u;
return pa[u] = findset(pa[u]);
}
int main(){
ios_base::sync_with_stdio(0);cin.tie(0);
cin >> n >> k;
for(int i=0;i<n;++i){
cin >> arr[i];
s[i] = i;
pa[i] = i;
}
sort(s, s+n-1, comp);
for(int i=0;i<n-k;++i){
int u = findset(s[i]), v = findset(s[i] + 1);
pa[v] = u;
res += (arr[s[i] + 1] - arr[s[i]]);
}
for(int i=0;i<n;++i){
int u = findset(i);
if(!fg[u]){
fg[u] = 1;
++res;
}
}
cout << res;
}
