program z9_21;
uses crt;
var s:string;
ch:char;
procedure double(c:char; var s:string);
var i:integer;
BEGIN
i:=1;
while i<=length(s) do begin
if s[i]=c then begin
insert(c,s,i+1);
inc(i);
end;
inc(i);
end;
end;
BEGIN
write('vvedite text');
readln(s);
write('vvedite bykvy');
readln(ch);
double(ch,s);
writeln('rezultat',s);
readln;
END.