#define _CRT_SECURE_NO_WARNINGS #include #include #include #include #include #include #include #include #include #include #include #include #include //#include "util.h" using namespace std; typedef long long ll; typedef unsigned long long ull; #define PI 3.14159265358979323846 #define EPS 1e-6 #define MIN(a,b) ((a)<(b)?(a):(b)) #define MAX(a,b) ((a)>(b)?(a):(b)) #define CHAR_BIT 8 #define all(x) (x).begin(), (x).end() template ostream& operator << (ostream& ostr, const vector<_Ty>& v) { if (v.empty()) { cout << "{ }"; return ostr; } cout << "{" << v.front(); for (auto itr = ++v.begin(); itr != v.end(); itr++) { cout << ", " << *itr; } cout << "}"; return ostr; } ll GCD(ll m, ll n) { ll k; do { k = m % n; m = n; n = k; } while (k != 0); return m; } int yuki0144() { int N; double P, ans = 0; cin >> N >> P; vector p(N + 1, 1.0); p[0] = p[1] = 0; for (int i = 2; i <= N; i++) { ans += p[i]; for (int j = 2 * i; j <= N; j += i) p[j] *= 1 - P; } printf("%.10f\n", ans); return 0; } int main() { //clock_t start, end; //start = clock(); yuki0144(); //end = clock(); //printf("%d msec.\n", end - start); return 0; }