#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define ff first
#define ss second
#define pii pair<int,int>
#define pb push_back
#define eb emplace_back
#define ins insert
#define endl "\n"
#define flush fflush(stdout)
#define deb(x) cout<<(x)<<endl
#define all(x) (x).begin(),(x).end()
#define dbg(x) cout<<#x<<" "<<x<<endl
const ll INF=1e18,MOD=1e9+7,MAXN=1e5+5;
int tt=1,n,k;
void solve(){
cin>>n>>k; int A[n]; priority_queue<int> pq;
for(int i=0;i<n;i++) {
cin>>A[i];
} sort(A,A+n);
for(int i=1;i<n;i++) pq.push(A[i] - A[i-1]);
int ans = 1; k--;
while(k) {
ans++;
pq.pop(); k--;
}
while(pq.size()) {
ans += pq.top(); pq.pop();
} deb(ans);
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(nullptr);
// cin>>tt;
while(tt--){
solve();
}
}
