#include "bits/stdc++.h" using namespace std; /* macro */ #define rep(i,a,b) for(int i=a;i b; i--) #define int long long #define exist(s,e) ((s).find(e)!=(s).end()) #define all(v) (v).begin(), (v).end() #define each(s,itr) for(auto (itr) = s.begin(); (itr) != s.end(); (itr)++) #define sum(v) accumulate(all(v), (0LL)) #define pb push_back /* alias */ template using vec = vector; typedef vector vi; typedef pair pi; /* constant */ const int inf = pow(2, 62); const int mod = 1e9 + 7; int dx[8]={1,0,-1,0,-1,1,-1,1}; int dy[8]={0,1,0,-1,-1,-1,1,1}; const string alpha = "abcdefghijklmnopqrstuvwxyz"; /* io_method */ int input(){int tmp;cin >> tmp;return tmp;} string raw_input(){string tmp;cin >> tmp;return tmp;} string readline(){string s;getline(cin, s);return s;} template void printx(T n){cout << n;} template void printx(pair p){cout << "(" << p.first << "," << p.second << ")";} template void printx(vector v){cout << "{";rep(i,0,v.size()){printx(v[i]);if(i != v.size()-1)printx(",");}cout << "}";} template void print(T n){printx(n);cout << endl;} template void print(set s){cout << "{";each(s, e){if(e != s.begin()) printx(",");printx(*e);}cout << "}" << endl;} template void print(map mp){cout << "{";each(mp, e){cout << "(" << e -> first << "," << e -> second << ")";}cout << "}" << endl;} /* general_method */ templatebool chmax(T &a, const T &b) { if (abool chmin(T &a, const T &b) { if (b void Fill(A (&array)[N], const T &val){ std::fill( (T*)array, (T*)(array+N), val ); } /* main */ signed main(){ cin.tie(0); ios::sync_with_stdio(false); int n, m;cin >> n >> m; vi arr; rep(i,0,n) arr.push_back(input()); sort(all(arr)); vi d; rep(i,1,n){ d.push_back(arr[i] - arr[i - 1]); } sort(all(d)); int ans = 0; rep(i,0,n - m){ ans += d[i]; } print(ans); }