program pat;
type
  point=^node;
   node=record
      x,v:longint; next:point;
   end;
var
  a:array[0..100000]of point;
  f1,f2,s1,s2:array[0..100000]of longint;
  n,i,m,max,k,x,y,ans:longint; p:point;
procedure add(x,y:longint);
var p:point;
begin
  new(p); p^.x:=y; p^.v:=1; p^.next:=a[x]; a[x]:=p;
end;
procedure dfs(x,e:longint);
var p:point; y:longint;
begin
  s1[x]:=x; s2[x]:=x;
  new(p); p:=a[x];
  while p<>nil do
   begin
     y:=p^.x;
     if y=e then begin p:=p^.next; continue; end;
     dfs(y,x);
     if f1[y]+p^.v>f1[x] then
     begin
       f2[x]:=f1[x]; s2[x]:=s1[x];
       f1[x]:=f1[y]+p^.v; s1[x]:=y;
      end
     else
     if f1[y]+p^.v>f2[x] then
     begin
       f2[x]:=f1[y]+p^.v; s2[x]:=y;
     end;
     p:=p^.next;
   end;
  if f1[x]+f2[x]>f1[max]+f2[max] then
   max:=x;
end;
procedure work(x:longint);
var p:point;  y:longint;
begin
  new(p); p:=a[x];
  while p<>nil do
   begin
     y:=p^.x;
     if y=s1[x] then begin p^.v:=-1; work(y); break; end;
     p:=p^.next;
   end;
end;
begin
  assign(input,‘pat.in‘);reset(input);
  assign(output,‘pat.out‘);rewrite(output);
  readln(n,k);
  for i:=1 to n-1 do
   begin
     readln(x,y); add(x,y);  add(y,x);
   end;
  ans:=2*(n-1); max:=0; f1[0]:=0; f2[0]:=0;
  dfs(1,0);
  ans:=ans-f1[max]-f2[max]+1;
  if k=1 then writeln(ans) else
   begin
     fillchar(f1,sizeof(f1),0);
     fillchar(f2,sizeof(f2),0);
     new(p); p:=a[max];
     while p<>nil do
      begin
        y:=p^.x;
        if (y=s1[max])or(y=s2[max]) then p^.v:=-1;
        p:=p^.next;
      end;
     work(s1[max]); work(s2[max]);  max:=0;
     dfs(1,0);
     ans:=ans-f1[max]-f2[max]+1;
     writeln(ans);
   end;
  close(input); close(output);
end.