#include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <cmath>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <bitset>
#include <cstring>
using namespace std;
#define FOR(I,A,B) for(int I = (A); I < (B); ++I)
#define CLR(mat) memset(mat, 0, sizeof(mat))
typedef long long ll;
int main()
{
  int N; cin >> N;
  double ans = 1;
  double hiku = 1;
  hiku = 6 * pow(5.0/6.0, N) - 15 * pow(4.0/6.0, N) + 20 * pow(3.0/6.0, N) - 15 * pow(2.0/6.0, N) + 6 * pow(1.0/6.0, N);
  ans -= hiku;
  printf("%.10lf\n", ans);
  return 0;
}