program oken;
uses crt;
var m,n,dem,i:integer;
begin
clrscr;
write('nhap M: '); readln(m);
write('nhap N: '); readln(n);
if m<n then
for i:=m to n do
if i mod 3 =0 then
dem:=dem+1;
writeln('tu ',m,' den ',n,' co ',dem,' chia het cho 3');
readln;
end.