program aa;
var
a,k,b,c,d,e,f,i,j,m,n,max,sum:longint;
l:array[1..100000]of longint;
f1,f2:text;
begin
assign(f1,'mushroom.in');
assign(f2,'mushroom.out');
reset(f1);
rewrite(f2);
readln(f1,n);
k:=1;l[1]:=2;
for i:=1 to n-1 do
begin
for j:=1 to k do
begin
if l[j]=1 then
l[j]:=2
else
begin
inc(k);
l[k]:=l[j]+1;
l[j]:=l[j]-1;
end;
end;
end;
writeln(f2,k);
close(f1);close(f2);
end.