var
 f:Array[1..1000,1..1000] of longint;
 i,j,m,n,x,y,l,ans,k:longint;
begin
 assign(input,'routea.in');reset(input);
 assign(output,'routea.out');rewrite(output);
 readln(n,k);
 fillchar(f,sizeof(f),$7f div 3);
 for i:=1 to n-1 do
  begin
   readln(x,y);
   f[x,y]:=1;
   f[y,x]:=1;
  end;
 for l:=1 to n do
  for i:=1 to n do
   for j:=1 to n do
    begin
     if f[i,l]+f[l,j]<f[i,j] then
      f[i,j]:=f[i,l]+f[l,j];
     if  (f[i,j]<100000) and(f[i,j]>ans) then ans:=f[i,j];
    end;
 writeln(ans div (2*k)+1);
 close(input);close(output);
end.