5.III.4

#include <iostream>
#include <string>
using namespace std;
int main()
{
    double e, s=0, a=1;
    int i=1;
    cin>>e;
    a=1.0/i*(i+1);
    while (a>e){
         a=1.0/i*(i+1);
        s+=a;
        ++i;
       }
        cout<<s<<endl;
    return(0);
    }