#include <cmath>
#include <iomanip>
#include <iostream>
#include <limits>
#include <map>
#include <set>
#include <string>
#include <vector>
using namespace std;
typedef long long ll;

#define rep(i, init, end) for(ll i = init; i < end; i++)
#define REP(i, init, end) for(ll i = init; i < end + 1; i++)
#define rev(i, end, init) for(ll i = init - 1; i >= end; i--)
#define REV(i, end, init) for(ll i = init; i >= end; i--)
#define PI 3.14159265359
#define EPS 0.0000000001
#define MOD 1000000007
//cout << std::fixed << std::setprecision(15) << y << endl;


double g(ll n){
    double ans = 1.0;
    for(ll i = 1; i <= n; i++){
        ans *= (double)i;
    }

    return ans;
}

int main(){
    double x;
    cin >> x;

    double sum[10000];
    double a, b, c;
    ll p = 0;
    a = 1.0, b = 1.0, c = 1123.0 / 1103.0;
    sum[0] = a * b * c;
    while(abs(sum[p]) > 1e-20){
        p++;
        a *= -1.0 * pow(22, 5) * pow(882, 3) / (pow(49, 5) * 4.0 * 99.0);
        b = 1.0 / g(4 * p - 2) * (4 * p - 2);
        c = (1123.0 + 21460.0 * (double)p) / (1103.0 + 26390.0 * (double)p);
        sum[p] = a * b * c;
    }

    double ans = 24.0 / 882.0 * sqrt(99) * x;
    double sumAll = 0;
    rep(i, 0, p){
        sumAll += sum[p];
    }
    cout << fixed << setprecision(20) << ans * sumAll << endl;

    return 0;
}