Vote cho mình nha ^^

uses crt;
var
    n,i,k,y,s,t,x,d:integer;
    a:array[1..1000] of integer;
begin
 clrscr;
 write('Nhap n: '); readln(n);
 for i:=1 to n do
  begin
   write('Nhap a[',i,']: ');
   readln(a[i]);
  end;
  for i:=1 to n do if (a[i] mod 2 = 0) then s:=s+a[i];
  writeln('Tong so chan: ',s);
  write('Nhap k: '); readln(k);
  for i:=1 to n do if (a[i] mod k = 0) then t:=t+a[i];
  writeln('Tong cac so chia het cho ',k,' : ',t);
  write('Nhap so X: '); readln(x);
  for i:=1 to n do if (a[i]=x) then d:=d+1;
  writeln(x,' xuat hien ',d,' lan');
  write('Nhap Y: '); readln(y);
  for i:=1 to n do if(a[i]=x) then a[i]:=y;
  writeln('Mang sau khi thay: ');
  for i:=1 to n do write(a[i],' ');

 readln;
end.