program madition(input,output);
var
 la,lb,ll:longint;
 a,b:array[1..200]of longint;
 n:longint;
 i,k:longint;
 s1,s2:string;

begin
 assign(input,'madition.in');
 reset(input);
 readln(n);
 readln(s1);
 readln(s2);
 close(input);

 la:=length(s1);
 lb:=length(s2);

 for i:=1 to la do
 begin
  if ('0'<=s1[la-i+1])and(s1[la-i+1]<='9') then
   a[i]:=ord(s1[la-i+1])-ord('0');
  if ('a'<=s1[la-i+1])and(s1[la-i+1]<='z') then
   a[i]:=ord(s1[la-i+1])-ord('a')+10;
 end;
 for i:=1 to lb do
 begin
  if ('0'<=s2[lb-i+1])and(s2[lb-i+1]<='9') then
   b[i]:=ord(s2[lb-i+1])-ord('0');
  if ('a'<=s2[lb-i+1])and(s2[lb-i+1]<='z') then
   b[i]:=ord(s2[lb-i+1])-ord('a')+10;
 end;

 if la>lb then ll:=la else ll:=lb;
 k:=0;
 for i:=1 to ll do
 begin
  a[i]:=a[i]+b[i]+k;
  k:=a[i] div n;
  a[i]:=a[i] mod n;
 end;
 la:=ll;
 if k>0 then
 begin
  a[ll+1]:=k;
  la:=ll+1;
 end;

 assign(output,'madition.out');
 rewrite(output);
 for i:=la downto 1 do
 begin
  if (a[i]>=0)and(a[i]<=9) then write(a[i])
  else if (a[i]>=10) then write(chr(a[i]-10+ord('a')));
 end;
 close(output);
end.