var f1,f2:text;
    x,xa,ds:array[0..1000] of longint;
    i,n:longint;

procedure fibo(nr:longint);
var i,r:longint;
begin
        r:=0;
        ds:=x;
        for i:=1 to x[0] do
        begin
                x[i]:=x[i]+xa[i]+r;
                r:=x[i] div 10;
                x[i]:=x[i] mod 10;
        end;
        while r>0 do
        begin
                inc(x[0]);
                x[x[0]]:=r mod 10;
                r:=r div 10;
        end;
        xa:=ds;
        if nr<n then
                fibo(nr+1);
end;


begin
        assign(f1,'nunta.in');
        reset(f1);
        assign(f2,'nunta.out');
        rewrite(f2);
        read(f1,n);
        x[0]:=1;
        x[1]:=1;
        fibo(1);
        for i:=x[0] downto 1 do
                write(f2,x[i]);
        close(f1);
        close(f2);
end.