type vect =array[1..100000000] of byte;
     var v1,v2,v:vect;
          i,k,m:integer;
          f,g:text;
procedure sum_m(var v1,v2,v:vect);
var i,tr:byte;
begin
 tr:=0;
 for i:=1 TO m do
  begin
   v[i]:=v1[i]+v2[i]+tr;
   tr:=v[i] div 10;
   v[i]:=v[i] mod 10;
  end;
 if tr<>0 then
  begin
   m:=m+1;
   v[m]:=tr;
  end;
v1:=v2;
v2:=v;
end;

BEGIN
 m:=1;
assign(f,'kfib.in');
reset(f);
read(f,k);
close(f);
 v1[1]:=1;
 v2[1]:=1;
 for i:=1 to k-2 do
 sum_m(v1,v2,v);

assign(g,'kfib.out');
rewrite(g);
for i:=m downto 1 do
write(g,v[i]);
close(g);

END.