using System; using System.Collections.Generic; using System.Linq; using System.IO; using System.Text; using System.Numerics; using static System.Math; using static System.Array; using static AtCoder.IO_ShortCut; using static AtCoder.Tool; using static AtCoder.ModInt; namespace AtCoder { class AC { const int MOD = 1000000007; //const int MOD = 998244353; const int INF = int.MaxValue / 2; const long SINF = long.MaxValue / 2; const double EPS = 1e-8; static readonly int[] dI = { 0, 1, 0, -1, 1, -1, -1, 1 }; static readonly int[] dJ = { 1, 0, -1, 0, 1, 1, -1, -1 }; static List> G = new List>(); //static List> G = new List>(); //static List E = new List(); static void Main(string[] args) { var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };Console.SetOut(sw); Solve(); Console.Out.Flush(); } static void Solve() { Input(out int N, out int K); var a = _ReadSplitLong; Sort(a); var difs = new List(); long ans = 0; for(var i = 0; i < N - 1; i++) { var nx = a[i + 1] - a[i]; ans += nx; difs.Add(nx); } difs.Sort();difs.Reverse(); for (var i = 0; i < K - 1; i++) { ans -= difs[i]; } OutL(ans); } struct Edge { public int from; public int to; public long dist; public Edge(int t, long c) { from = -1; to = t; dist = c; } public Edge(int f, int t, long c) { from = f; to = t; dist = c; } } } struct ModInt { public long value; private const int MOD = 1000000007; //private const int MOD = 998244353; public ModInt(long value) { this.value = value; } public static implicit operator ModInt(long a) { var ret = a % MOD; return new ModInt(ret < 0 ? (ret + MOD) : ret); } public static ModInt operator +(ModInt a, ModInt b) => (a.value + b.value); public static ModInt operator -(ModInt a, ModInt b) => (a.value - b.value); public static ModInt operator *(ModInt a, ModInt b) => (a.value * b.value); public static ModInt operator /(ModInt a, ModInt b) => a * Modpow(b, MOD - 2); public static ModInt operator <<(ModInt a, int n) => (a.value << n); public static ModInt operator >>(ModInt a, int n) => (a.value >> n); public static ModInt operator ++(ModInt a) => a.value + 1; public static ModInt operator --(ModInt a) => a.value - 1; public static ModInt Modpow(ModInt a, long n) { var k = a; ModInt ret = 1; while (n > 0) { if ((n & 1) != 0) ret *= k; k *= k; n >>= 1; } return ret; } private static readonly List Factorials = new List() { 1 }; public static ModInt Fac(long n) { for (var i = Factorials.Count(); i <= n; i++) { Factorials.Add((Factorials[i - 1] * i) % MOD); } return Factorials[(int)n]; } public static ModInt nCr(long n, long r) { return n < r ? 0 : Fac(n) / (Fac(r) * Fac(n - r)); } public static explicit operator int(ModInt a) => (int)a.value; } static class IO_ShortCut { public static string[] _ReadSplit => Console.ReadLine().Split(); public static int[] _ReadSplitInt => ConvertAll(Console.ReadLine().Split(), int.Parse); public static long[] _ReadSplitLong => ConvertAll(Console.ReadLine().Split(), long.Parse); public static double[] _ReadSplit_Double => ConvertAll(Console.ReadLine().Split(), double.Parse); public static string Str => Console.ReadLine(); public static int Int => int.Parse(Console.ReadLine()); public static long Long => long.Parse(Console.ReadLine()); public static double Double => double.Parse(Console.ReadLine()); public static T Conv(string input) { if (typeof(T).Equals(typeof(ModInt))) { return (T)(dynamic)(long.Parse(input)); } return (T)Convert.ChangeType(input, typeof(T)); } public static void Input(out T a) => a = Conv(Console.ReadLine()); public static void Input(out T a, out U b) { var q = _ReadSplit;a = Conv(q[0]);b = Conv(q[1]); } public static void Input(out T a, out U b, out V c) { var q = _ReadSplit;a = Conv(q[0]);b = Conv(q[1]);c = Conv(q[2]); } public static void Input(out T a, out U b, out V c, out W d) { var q = _ReadSplit; a = Conv(q[0]); b = Conv(q[1]); c = Conv(q[2]);d = Conv(q[3]); } public static void OutL(object s) => Console.WriteLine(s); public static void Out_Sep(IEnumerable s) => Console.WriteLine(string.Join(" ", s)); public static void Out_Sep(IEnumerable s, string sep) => Console.WriteLine(string.Join($"{sep}", s)); public static void Out_Sep(params object[] s) => Console.WriteLine(string.Join(" ", s)); public static void Out_One(object s) => Console.Write($"{s} "); public static void Out_One(object s, string sep) => Console.Write($"{s}{sep}"); public static void Endl() => Console.WriteLine(); } public static class Tool { static public void Initialize(ref T[] array, T initialvalue) { array = ConvertAll(array, x => initialvalue); } static public void Swap(ref T a, ref T b) { T keep = a; a = b; b = keep; } static public void Display(T[,] array2d, int n, int m) { for (var i = 0; i < n; i++) { for (var j = 0; j < m; j++) { Console.Write($"{array2d[i, j]} "); } Console.WriteLine(); } } static public long LPow(int a, int b) => (long)Pow(a, b); static public bool Bit(long x, int dig) => ((1L << dig) & x) != 0; } }