#include using namespace std; typedef long long ll; #define REP(i,n) for(int i=0; i #define VLL vector #define VVI vector> #define VVLL vector> #define VC vector #define VS vector #define VVC vector> #define fore(i,a) for(auto &i:a) typedef pair P; template bool chmax(T &a, T b) { if (a < b) { a = b; return true; } return false; } template bool chmin(T &a, T b) { if (a > b) { a = b; return true; } return false; } const int INF = 2147483647; const ll INFL = 9223372036854775807; const ll mod = 1000000007; int main() { int n, k; cin >> n >> k; VLL a(n); REP(i, n)cin >> a[i]; sort(ALL(a)); VLL v(n - 1); REP(i, n - 1) { v[i] = a[i + 1] - a[i]; } sort(ALL(v)); ll ans = 0; REP(i, n - k) { ans += v[i]; } cout << ans << endl; return 0; }