program songuyento;
uses crt;
var n,i : integer;
function snt(x : integer) : boolean;
var d,i : integer;
begin d:=0;
for i:=1 to x do if x mod i = 0 then d:=d+1;
if d=2 then snt:=true else snt:=false;
end;
begin clrscr;
write('Nhap so n :'); readln(n);
write('Cac so nguyen to tu 1 den ',n,' la :');
for i:=1 to n do if snt(i) = true then write(i:3);
readln
end.