#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 using namespace std; #define int long long #define let const auto #define var auto #define all(c) c.begin(), c.end() #define repeat(i, n) for (int i = 0; i < static_cast(n); i++) #define debug(x) #x << "=" << (x) #ifdef DEBUG #define dump(x) std::cerr << debug(x) << " (L:" << __LINE__ << ")" << std::endl #else #define dump(x) #endif typedef complex point; template ostream &operator<<(ostream &os, const vector &v) { os << "{"; for(auto it = v.begin(); it != v.end(); ++it){ if(it != v.begin()){ os << ","; } os << *it; } return os << "}"; } template void isort(std::vector& v, std::function comp=less()){ sort(v.begin(), v.end(), comp); } template std::vector sort(std::vector v, std::function comp=less()){ isort(v); return v; } template std::vector rmap(const std::vector& v, std::function f){ std::vector t; t.reserve(v.size()); for(const auto& i: v) t.push_back(f(i)); return t; } std::vector split(std::string str, char delim){ std::vector res; size_t current = 0, found; while((found = str.find_first_of(delim, current)) != std::string::npos){ res.push_back(std::string(str, current, found - current)); current = found + 1; } res.push_back(std::string(str, current, str.size() - current)); return res; } string join(const std::vector& v, string delim){ string ret = ""; for(auto it = v.begin(); it != v.end(); ++it){ if(it != v.begin()){ ret += delim; } ret += *it; } return ret; } double solve(int n, double p){ vector is_prime(n+1, 1.0); is_prime[0] = 0.0; is_prime[1] = 0.0; double ret = 0; for(int i=2;i<=n;i++){ ret += is_prime[i]; for(int k=2; k*i <= n; k++){ is_prime[k*i] *= (1-p); } } return ret; } signed main() { ios::sync_with_stdio(false); cin.tie(0); cout << fixed << setprecision(10); int n; double p; cin >> n >> p; auto ret = solve(n, p); cout << ret << endl; return 0; }