program xoa;
Uses crt;
var s1,s2:string;
i:byte;
begin
clrscr;
write('Nhap xau thu nhat: '); readln(s1);
write('Nhap xau thu hai: '); readln(s2);
i:=1;
while i<=length(s1) do
if pos(s1[i],s2)<>0 then delete(s1,i,1)
else i:=i+1;
wrie('Xau thu nhat sau khi lam viec la: ',s1);
readln;
end.