program fibonachi3;
uses
  SysUtils,Windows;
{$APPTYPE CONSOLE}

var t,f1,f2,f3:string;

os, n,i,j:integer;
//time:int64;
begin
time:=GetTickCount;
readln(n);
f1:='1';f2:='1';
for i:=2 to n do
begin
os:=0;
while length(f1)<length(f2) do f1:='0'+f1;
f3:='';
for j:=length(f2) downto 1 do
begin
f3:=f3+inttostr((strtoint(f1[j])+strtoint(f2[j])+os) mod 10);
os:=(strtoint(f1[j])+strtoint(f2[j])+os)div 10;
end;
if os>0 then f3:=inttostr(os)+f3;
f1:=f2;
f2:=f3;
end;
writeln(f2);
//time:=GetTickCount-time;
//writeln((time/1000):0:5);
readln;
end.