program madition(input,output);

type
  spn=array[0..200]of byte;

var
  n,i:integer;
  a,b,t:spn;
  ch:char;

procedure add(const a,b:spn; var c:spn);
  var
    i,en,h:byte;
  begin
    if a[0]>b[0] then
      en:=a[0]
    else
      en:=b[0];

    h:=0;
    for i:=1 to en do
    begin
      c[i]:=a[i]+b[i]+h;

      if c[i]>=n then
      begin
        c[i]:=c[i]-n;
        h:=1;
      end
      else
        h:=0;
    end;

    if h=1 then
    begin
      c[en+1]:=1;
      c[0]:=en+1;
    end
    else
      c[0]:=en;
  end;

begin
  assign(input,'madition.in');
  reset(input);
  assign(output,'madition.out');
  rewrite(output);

  readln(n);
  read(ch);
  t[0]:=0;
  while ch>='0' do
  begin
    inc(t[0]);

    if ch in['0'..'9'] then
      t[t[0]]:=ord(ch)-ord('0')
    else
      t[t[0]]:=ord(ch)-ord('a')+10;

    read(ch);
  end;
  readln;

  a[0]:=t[0];
  for i:=1 to t[0] do
    a[i]:=t[t[0]-i+1];

  read(ch);
  t[0]:=0;
  while ch>='0' do
  begin
    inc(t[0]);

    if ch in['0'..'9'] then
      t[t[0]]:=ord(ch)-ord('0')
    else
      t[t[0]]:=ord(ch)-ord('a')+10;

    read(ch);
  end;

  b[0]:=t[0];
  for i:=1 to t[0] do
    b[i]:=t[t[0]-i+1];

  add(a,b,t);

  for i:=t[0] downto 1 do
    if t[i]<10 then
      write(t[i])
    else
      write(chr(t[i]-10+ord('a')));
  writeln;

  close(input);
  close(output);
end.