program nguyentodoixung;
uses crt;
var a,b,i,d:integer;
function ktnt(k:integer):boolean;
var l:integer;
begin
ktnt:=false;
if k<2 then exit;
for l:=2 to trunc(sqrt(k)) do
if k mod l=0 then exit;
ktnt:=true;
end;
function ktdx(k:integer):boolean;
var h,m:integer;
begin
h:=0; m:=k;
while m>0 do
begin
h:=h*10+m mod 10;
m:=m div 10;
end;
if h=k then ktdx:=true else ktdx:=false;
end;
BEGIN
clrscr;
write('Nhap a: '); readln(a);
write('Nhap b: '); readln(b);
d:=0;
for i:=a to b do
if ktnt(i) and ktdx(i) then
begin
write(i,' ');
d:=d+1;
end;
if d=0 then write('Khong co so nguyen to doi xung nao')
else write('=> Co ',d,' so nguyen to doi xung tu ',a,' den ',b);
readln
end.