#include #include #include #include #include #include #include #include #include #include #include #include #define vll vector #define vvvl vector #define vvl vector> #define VV(a, b, c, d) vector>(a, vector(b, c)) #define VVV(a, b, c, d) vector(a, vvl(b, vll (c, d))); #define re(c, b) for(ll c=0;c> n; ld p;std::cin >> p; vll cnt(n+1, 0); for(ll i=2;i<=n;i++){ for(ll j=2*i;j<=n;j+=i){ cnt[j]++; } } ld ans = 0; for(int i=2;i<=n;i++) ans += pow((1.0-p), cnt[i]); cout << fixed << setprecision(20) << ans << "\n"; //iが素数に含まれる確率(1-p)^cnt[i] }