program baigiai;
uses crt;
var a,b,i,d,j,k:integer;
begin
clrscr;
write('Nhap a: '); readln(a);
write('Nhap b: '); readln(b);
writeln('Cac so nguyen to la: ');
k:=0;
for i:=a to b do
begin
d:=0;
for j:=2 to i div 2 do
if i mod j=0 then d:=d+1;
if d=0 then write(i,' ');
end;
if k=0 then write('Khong co nha.');
writeln;
while a<>b do
if a>b then a:=a-b else b:=b-a;
write('uocchunglonnhat la: ',a);
readln;
end.