Program exer (input,output);
var i,N,p,c:integer;
begin
    readln (N);
    i:=1;
    c:=i mod 10;
    p:=0;
    while (i<=N)) do
          begin
          if (i=2) or (i=5) or (c=1) or (c=3) or (c=7) or (c=9) and
                      begin
                      p:=p+1;
                      i:=i+1;
                      c:= i mod 10;
                      end;
           end;
     writeln (p);
end.