记录编号	22476	评测结果	AAAAAAAAAA
题目名称	515.象棋比赛	最终得分	100
用户昵称	donny	是否通过	通过
代码语言	Pascal	运行时间	0.102 s
提交时间	2010-11-19 14:36:46	内存使用	0.87 MiB

program chess;
var
  n,k,i,j,l:longint;
  a:array[1..100000]of longint;
  m:array[1..100000]of longint;
  max:longint;
procedure sort(const x,y:longint);
var
  i,j,k,l:longint;
begin
  i:=x;
  j:=y;
  k:=a[(x+y)div 2];
  repeat
    while a[i]<k do inc(i);
    while a[j]>k do dec(j);
    if i<=j then
    begin
      l:=a[i];
      a[i]:=a[j];
      a[j]:=l;
      inc(i);
      dec(j);
    end;
  until i>j;
  if x<j then sort(x,j);
  if i<y then sort(i,y);
end;
procedure sortt(const x,y:longint);
var
  i,j,k,l:longint;
begin
  i:=x;
  j:=y;
  k:=m[(x+y)div 2];
  repeat
    while m[i]<k do inc(i);
    while m[j]>k do dec(j);
    if i<=j then
    begin
      l:=m[i];
      m[i]:=m[j];
      m[j]:=l;
      inc(i);
      dec(j);
    end;
  until i>j;
  if x<j then sortt(x,j);
  if i<y then sortt(i,y);
end;
begin
  assign(input,'chess.in');
  reset(input);
  assign(output,'chess.out');
  rewrite(output);
  readln(n,k);
  for i:=1 to n do
    readln(a[i]);
  sort(1,n);
  for i:=1 to n-1 do
    m[i]:=a[i+1]-a[i];
  sortt(1,n-1);
  max:=0;
  for i:=1 to k do
    max:=max+m[i];
  writeln(max);
  close(input);
  close(output);
end.