#include <iostream>
#include <iomanip>
#include <bitset>
using namespace std;

double prop[1000010][1 << 6];

int main() {
    int N;
    cin >> N;

    prop[0][0] = 1;
    for (int i = 0; i < N; i++) {
        for (int mask = 0; mask < (1 << 6); mask++) {
            for (int d = 0; d < 6; d++) {
                if ((mask >> d) & 1) {
                    prop[i + 1][mask] += prop[i][mask & ~(1 << d)] / 6.0;
                    prop[i + 1][mask] += prop[i][mask] / 6.0;
                }
            }
        }
    }
    cout << fixed << setprecision(10) << prop[N][(1 << 6) - 1] << endl;

    /*
    for (int i = 0; i < N; i++) {
        for (int mask = 0; mask < (1 << 6); mask++) {
            bitset<6> bits(mask);
            cerr << i + 1 << " " << bits << " " << prop[i + 1][mask] << endl;
        }
    }
    */

    return 0;
}