program divide;
 const
   maxn=1000;
 var
     n,m,k,c:longint;
     f:array[0..maxn,1..maxn] of int64;
     gmax,gmin:array[1..maxn,1..maxn] of longint;
     a:array[1..maxn*10] of longint;



function max(a,b,c:longint):longint;
 begin
  if a>b then max:=a else max:=b;
  if c>max then max:=c;
 end;


function min(a,b,c:longint):longint;
 begin
  if a<b then min:=a else min:=b;
  if c<min then min:=c;
 end;


procedure init;
  var
      i,j:integer;
 begin
  readln(n,k,c); m:=n div k;

  for i:=1 to n do read(a[i]);
  for i:=1 to n do
    begin
     gmax[i,i]:=a[i];
     gmin[i,i]:=a[i];
    end;

   for i:=n-1 downto 1 do
    for j:=i+1 to n do
     begin
       gmax[i,j]:=max(gmax[i,j],gmax[i+1,j],a[i]);
       gmax[i,j]:=max(gmax[i,j],gmax[i,j-1],a[j]);
       gmin[i,j]:=maxlongint;
       gmin[i,j]:=min(gmin[i,j],gmin[i+1,j],a[i]);
       gmin[i,j]:=min(gmin[i,j],gmin[i,j-1],a[j]);
     end;

 end;



procedure main;
 var
    i,j,p:longint;
    tm,ans:int64;

 begin
  for i:=1 to n do
  f[i,1]:=sqr(gmax[1,i]-gmin[1,i])+c;
  for j:=2 to m do
   for i:=j*k to n do
    begin
     f[i,j]:=maxlongint;
       for p:=(j-1)*k to i-k do
        begin
          tm:=f[p,j-1]+sqr(gmax[p+1,i]-gmin[p+1,i])+c;
       if tm<f[i,j]
       then f[i,j]:=tm;
       end;
    end;
  ans:=f[n,1];
  for i :=2 to m do
  if f[n,i]<ans then ans:=f[n,i];
  writeln(ans);
 end;


begin
  assign(input,'divide.in');
  assign(output,'divide.out');
  reset(input); rewrite(output);
  init;
  main;
  close(input); close(output);
end.