2 câu trả lời
program bai_giai;
uses crt;
var s:string;
i:integer;
begin
clrscr;
readln(S);
for i:=lenght(s) downto 1 do
if s[i] in ['0'..'9'] then write(s[i]);
readln;
end.
uses crt;
var s:string;
i:integer;
begin
clrscr;
readln(S);
for i:=s downto 1 do
if s[i] in ['0'..'9'] then write(s[i]);
readln;
end.
