var n,i,j:longint; d:array[-1..5000,1..1500]of longint;PRocedure add(k:longint);var i,j,g,a,b,c:longint;begin a:=k-2;b:=k-1;c:=k; g:=0; for i:=1 to 1500 do begin d[c,i]:=d[a,i]+d[b,i]+g; g:=d[c,i] div 10; d[c,i]:=d[c,i] mod 10; end;end;begin readln(n); if n=0 then begin writeln('0');halt;end; d[0,1]:=1; for i:=1 to n do add(i); i:=1500; while (d[n,i]=0)and(i>1) do dec(i); for j:=i downto 1 do write(d[n,j]);end.
