#include <bits/stdc++.h>
using namespace std;
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define ALL(v) begin(v),end(v)
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
using ll = long long;
using pii = pair<int, int>;
constexpr ll INF = 1ll<<30;
constexpr ll longINF = 1ll<<60;
constexpr ll MOD = 1000000007;
constexpr bool debug = false;
//---------------------------------//

int main() {
	int N;
	cin >> N;
	double dp[2][1 << 6];
	dp[0][0] = 1;
	REP(i, N) {
		const int cur = i & 1, nex = cur ^ 1;
		fill(dp[nex], dp[nex + 1], 0);
		REP(j, 1 << 6) REP(k, 6) dp[nex][j | 1 << k] += dp[cur][j] / 6;
	}
	printf("%.16f\n", dp[N & 1][(1 << 6) - 1]);
}