Why my program is wrong,who can help me.
  This is my program:
   var
  a:array [0..100,0..100] of longint;
  s,b:array [0..100] of longint;
  used:array [1..100] of boolean;
  i,j,m,n,q,l,k,ans:longint;
 procedure cal(k:longint);
  var
   i,j:longint;
  begin
   used[k]:=true;
   for i:=1 to n do
    if (a[k,i]<>-1) and (not used[i]) then
     begin
      cal(i);
      b[k]:=b[k]+b[i]+1;
      s[k]:=s[k]+s[i]+a[k,i];
     end;
  end;
 function del(k,m:longint):longint;
  var
   i,j,min,k1,k2,mink,ss,t:longint;
  begin
   if m=0 then begin
    del:=0;
    exit;
   end;
   used[k]:=true;
   if m=b[k]
    then del:=s[k]
    else begin
     k1:=0; k2:=0;
     for i:=1 to n do
      if (a[k,i]<>-1) and (not used[i]) then
       if k1=0 then k1:=i
               else k2:=i;
     min:=maxlongint;
     if m>b[k1] then min:=s[k1]+a[k,k1]+del(k2,m-b[k1]-1);
     if m>b[k2] then begin
      ss:=s[k2]+a[k,k2]+del(k1,m-b[k2]-1);
      if min>ss then min:=ss;
     end;
     for i:=m-b[k2] to b[k1] do begin
      ss:=del(k1,i);
      ss:=del(k2,m-i)+ss;
      if ss<min then min:=ss;
     end;
     del:=min;
    end;
   used[k]:=false;
  end;
 begin
  readln(n,q);
  for i:=0 to 100 do
   for j:=0 to 100 do
    a[i,j]:=-1;
  for k:=1 to n-1 do begin
   readln(i,j,l);
   a[i,j]:=l;
   a[j,i]:=l;
  end;
  fillchar(used,sizeof(used),false);
  cal(1);
  s[0]:=0; b[0]:=0;
  fillchar(used,sizeof(used),false);
  ans:=s[1]-del(1,n-q-1);
  writeln(ans);
 end.