#include <bits/stdc++.h> #define rep(i,n)for(int i=0;i<(n);i++) #define EPS (1e-9) using namespace std; double dp[500][1<<6]; int main(){ int n;scanf("%d",&n); dp[0][0]=1; rep(i,n){ if(abs(dp[i][(1<<6)-1]-1)<EPS){ printf("%.12lf\n",1.0); return 0; } rep(j,1<<6){ if(dp[i][j]==0)continue; rep(k,6){ dp[i+1][j|1<<k]+=dp[i][j]/6; } } } printf("%.12lf\n",dp[n][(1<<6)-1]); }