uses crt;
var n: integer;
kt: boolean;
function nt(n: integer): boolean;
var i,d: integer;
begin
 d:=0;
 for i:=1 to n do
 if n mod i=0 then inc(d);
 if d=2 then nt:=true else nt:=false;
end;
begin
clrscr;
write ('nhap n: ');   readln (N);
kt:=true;
if nt(n)=true then
begin
repeat
n:=n div 10;
if nt(n)=false then kt:=false;
until n<10;
if kt=true then writeln ('day la sieu so nguyen to')
else if kt=false then writeln ('day khong phai la sieu so nguyen to');
end
else writeln ('day khong phai la sieu so nguyen to');
readln;
end.

program sieunt;
uses crt;
var n,i:longint;
function ktnt(m:longint):boolean;
var l:longint;
begin
 ktnt:=false;
 if m<2 then exit;
 for l:=2 to trunc(sqrt(m)) do
  if m mod l=0 then exit;
 ktnt:=true;
end;
function ktsnt(k:longint):boolean;
begin
  ktsnt:=false;
  while k>0 do
    begin
     if ktnt(k)=false then exit;
     k:=k div 10;
   end;
ktsnt:=true;
end;
BEGIN
clrscr;
write('Nhap n: ');
readln(n);
for i:=2 to n do
  if ktsnt(i) then write(i,' ');
readln
end.