#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX(a,b) (a > b) ? a : b
#define MIX(a,b) (a < b) ? a : b

int main(){
   int a;
   double b;
   scanf("%d",&a);
   b = 1/(double)a;
   printf("%lf\n",b);
}