{$APPTYPE CONSOLE}

var a,b,c:array [1..1000] of integer;
i,j,n,la,lb,lc:integer;
function summ(la,lb:integer):integer;
var i,max:integer;
begin
 max:=la;
 if (lb > la) then max:=lb;
 for i:=1 to max do
  begin
   c[i]:=c[i] + a[i] + b[i];
   c[i+1]:=c[i] div 10;
   c[i]:=c[i] mod 10;
  end;
 if (c[max+1]<>0) then summ:=max+1 else summ:=max;
end;
begin
 assign(input,′input.txt′); reset(input);
 assign(output,′output.txt′); rewrite(output);
 read(n); {f0=1 f1=1}
 a[1]:=1;
 b[1]:=1;
 la:=1;
 lb:=1;
 while n>1 do
  begin
   lc:=summ(la,lb);
   for j:=1 to lb do a[j]:=b[j];
    la:=lb;
   for j:=1 to lc do b[j]:=c[j];
    lb:=lc;
   fillchar(c,sizeof(c),0); 
   dec(n); 
  end;
 for i:=lb downto 1 do
  write(b[i]);
end.