#include <iostream>
#include <cmath>
using namespace std;
int n,d,NR,s,S1;
float ma,S;
int main(){
     cin>>n;
     for(d=1; d<=n; d++){
          if(n%d==0){
               s=s+d;
               NR++;
          }
      }
      ma=(float) s/NR;
      if(ma==(int)ma)    cout<<ma<<".00";
      else if(ma * 10 == int(ma * 10))    cout<<ma<<'0';
      else{
          ma=ma*100;
          S1=(int)ma;
          S=( float) S1/100;
          cout <<S;
      }
      return 0;
}