#define ENABLE_DEBUG 1 // Kana's kitchen {{{ #include #define ALL(v) std::begin(v),std::end(v) #define LOOP(k) for(i64 ngtkana_is_a_genius=0; ngtkana_is_a_genius<(i64)k; ngtkana_is_a_genius++) using i32 = std::int_least32_t; using i64 = std::int_least64_t; using u32 = std::uint_least32_t; using u64 = std::uint_least64_t; using usize = std::size_t; template using pair = std::pair; template using diag_pair = std::pair; template using tuple = std::tuple; template using vec = std::vector; template using numr = std::numeric_limits; #ifdef NGTKANA #include #else #define DEBUG(...)(void)0 #endif /*}}}*/ int main() { std::cin.tie(nullptr); std::ios::sync_with_stdio(false); std::cout << std::setprecision(15) << std::fixed; double p; std::cin >> p; std::cout << 1 / (1-p) - 1 << '\n'; }