var s:string;

n,i,num:longint;

procedure delmaxsubnum();

var i,ii:longint;

tmax:string;

begin

tmax:='0';

for i:=1 to length(s) do begin

if s[i]>tmax then begin ii:=i;tmax:=s[i];end;

end;

delete(s,ii,1);

end;

begin

readln(s);

readln(n);

for i:=1 to n do delmaxsubnum;

if s='' then write(0) else

begin val(s,num);write(num);end;

readln;readln;

end.