giup minh vs a sos thank you

var f:text;

s:string;

n,i,k,tam,m,c,j:longint;

A:array[0..10001] of longint;

begin

assign(F,'XSO.INP'); reset(F);

readln(f,n); readln(f,k); close(F);

assign(f,'XSO.out'); rewrite(F);

Str(n,s);

m:=1;

for i:=1 to length(S) do begin val(s[i],c); A[m]:=c; m:=m+1; end;

for i:=1 to length(S)-1 do

 for j:=i+1 to length(S) Do

 if a[i]<a[j] then 

begin 

tam:=a[i];

a[i]:=a[j];

a[j]:=tam;

end;

for i:=1 to length(S)-k do 

if a[i]>0 then write(f,a[i]);

close(F);

End.

CODE ăn điểm nhen ! .. 

Xin câu trả lời hay nhất ạ!