Program orz;
Const
 maxn=2501;
Var
 n,m,i,j,c:longint;
 d:array[1..maxn] of integer;
 e:array[0..maxn,0..1] of integer;
 f:array[0..maxn] of integer;

Function min(i,j:longint):longint;
 begin
  if i<j then
   exit(i);
  exit(j);
 end;

Function check(i,j:longint):boolean;
 begin
  if e[i,0]-e[j-1,0]=0 then
   exit(true);
  if e[i,1]-e[j-1,1]=0 then
   exit(true);
  if abs(abs(e[i,0]-e[j-1,0])-abs(e[i,1]-e[j-1,1]))<=c then
   exit(true);
  exit(false);
 end;

Begin
 assign(input,'orz.in');
 assign(output,'orz.out');
 reset(input);
 rewrite(output);
 readln(n,c);
 for i:=1 to n do
  begin
   readln(d[i]);
   if d[i]=1 then
    begin
     e[i,0]:=e[i-1,0]+1;
     e[i,1]:=e[i-1,1];
    end
   else
    begin
     e[i,1]:=e[i-1,1]+1;
     e[i,0]:=e[i-1,0];
    end;
  end;
 fillchar(f,sizeof(f),$7f);
 f[1]:=1;
 f[0]:=0;
 for i:=2 to n do
  for j:=1 to i-1  do
   begin
    if check(i,j) then
     f[i]:=min(f[i],f[j-1]+1);
   end;
 writeln(f[n]);
 close(input);
 close(output);
End.