#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* template start */ using i64 = std::int_fast64_t; using u64 = std::uint_fast64_t; #define rep(i, a, b) for (i64 i = (a); (i) < (b); (i)++) #define all(i) i.begin(), i.end() #ifdef LOCAL #define debug(...) \ std::cerr << "LINE: " << __LINE__ << " [" << #__VA_ARGS__ << "]:", \ debug_out(__VA_ARGS__) #else #define debug(...) #endif void debug_out() { std::cerr << std::endl; } template void debug_out(Head h, Tail... t) { std::cerr << " " << h; if (sizeof...(t) > 0) std::cout << " :"; debug_out(t...); } template std::ostream& operator<<(std::ostream& os, std::pair pa) { return os << pa.first << " " << pa.second; } template std::ostream& operator<<(std::ostream& os, std::vector vec) { for (std::size_t i = 0; i < vec.size(); i++) os << vec[i] << (i + 1 == vec.size() ? "" : " "); return os; } template inline bool chmax(T1& a, T2 b) { return a < b && (a = b, true); } template inline bool chmin(T1& a, T2 b) { return a > b && (a = b, true); } template constexpr Num mypow(Num a, u64 b, Num id = 1) { if (b == 0) return id; Num x = id; while (b > 0) { if (b & 1) x *= a; a *= a; b >>= 1; } return x; } /* template end */ int main() { std::cin.tie(nullptr); std::ios::sync_with_stdio(false); long double basel=1.6449340668482262l; i64 n; std::cin>>n; long double ans=pow(basel,n); ans/=n; std::cout<