#include <stdio.h>

int main () {
  int n,
    i;	      /* indice do i-esimo termo da seq  */
  double Hi;  /* H_i = H_{i-1} + 1/i */

  scanf ( "%d", &n );
  Hi = 0.0;

  for ( i = 1; i <= n; i++ )
    Hi = Hi + 1 / i;

  printf ( "%g\n", Hi );

  return 0;
}