uses crt;
var s:string;
dem:byte;
begin
clrscr;
write('Nhap vao 1 xau: '); readln(s);
dem:=0;
while pos('a',s)<>0 do
begin
dem:=dem+1;
delete(s,pos('a',s),1);
end;
while pos('A',s)<>0 do
begin
dem:=dem+1;
delete(s,pos('A',s),1);
end;
write('Trong xau co ',d,' chu cai a khong phan biet');
readln;
end.
