记录编号	81411	评测结果	AAAAAAAAAA
题目名称	象棋比赛	最终得分	100
用户昵称	TA	是否通过	通过
代码语言	Pascal	运行时间	0.041 s
提交时间	2013-11-13 12:11:37	内存使用	0.09 MiB

var
 n,k,i,j,h,ans,x:longint;
 a,r:array[1..100000] of longint;
procedure merge(s,m,t:longint);
var
 i,j,k:longint;
begin
 i:=s;
 j:=m+1;
 k:=s;
 while (i<=m) and (j<=t) do
  begin
   if a[i]<=a[j] then
     begin
      r[k]:=a[i];
      inc(i);
     end
    else
     begin
      r[k]:=a[j];
      inc(j);
     end;
   inc(k);
  end;
 while i<=m do
  begin
   r[k]:=a[i];
   inc(i);
   inc(k);
  end;
 while j<=t do
  begin
   r[k]:=a[j];
   inc(j);
   inc(k);
  end;
 for i:=s to t do
  a[i]:=r[i];
end;
procedure sort(s,t:longint);
 var
  m:longint;
 begin
  if s<t then
    begin
     m:=(s+t) div 2;
     sort(s,m);
     sort(m+1,t);
     merge(s,m,t);
    end;
 end;
begin
 assign(input,'chess.in');
 assign(output,'chess.out');
 reset(input);
 rewrite(output);
 //while not(eof) do
  //begin
   readln(n,k);
   for i:=1 to n do
    readln(a[i]);
   sort(1,n);
   for i:=1 to n-1 do
    a[i]:=a[i+1]-a[i];
   sort(1,n-1);
   ans:=0;
   for i:=1 to k do
    inc(ans,a[i]);
   writeln(ans);
  //end;
 close(input);
 close(output);
end.