#define _CRT_SECURE_NO_WARNINGS //#define _GLIBCXX_DEBUG #include using namespace std; typedef long long ll; typedef vector vi; typedef vector vvi; typedef pair pii; #define all(c) (c).begin(), (c).end() #define loop(i,a,b) for(ll i=a; i istream& operator>>(istream& is, vector& v); template ostream& operator<<(ostream& os, vector const& v); template typename enable_if<(n>=sizeof...(T))>::type _ot(ostream&, const tuple&){} template typename enable_if<(n< sizeof...(T))>::type _ot(ostream& os, const tuple& t){ os << (n==0?"":" ") << get(t); _ot(os, t); } template ostream& operator<<(ostream& os, const tuple& t){ _ot<0>(os, t); return os; } template typename enable_if<(n>=sizeof...(T))>::type _it(istream&, tuple&){} template typename enable_if<(n< sizeof...(T))>::type _it(istream& is, tuple& t){ is >> get(t); _it(is, t); } template istream& operator>>(istream& is, tuple& t){ _it<0>(is, t); return is; } template istream& operator>>(istream& is, vector& v){ rep(i,v.size()) is >> v[i]; return is; } template ostream& operator<<(ostream& os, vector const& v){ rep(i,v.size()) os << v[i] << (i+1==(int)v.size()?"":" "); return os; } #ifdef DEBUG #define dump(...) (cerr<<#__VA_ARGS__<<" = "<>N>>p){ // for(int i=2;i<=N;i++){ // dp[i] = 1; // for(int j=2;j*j<=i;j++){ // if(i%j==0){ // dp[i] *= (1-p)*dp[j]; // if(j*j!=i) dp[i] *= (1-p)*dp[i/j]; // } // } // } for(int i=2;i<=N;i++) dp[i] = 1; for(int i=2;i<=N;i++){ for(int j=i+i; j<=N; j+=i){ dp[j] *= p; } } double ans = 0; for(int i=2;i<=N;i++){ ans += dp[i]; } printf("%.10lf\n", ans); } } // memset(cnt,0,sizeof(cnt)); // for(int i=2;i<=1000000;i++){ // for(int j=i; j<=1000000; j+=i){ // cnt[j]++; // } // } // dump(vi(cnt, cnt+20)); // while(cin>>N>>p){ // double ans = 0; // for(int i=2;i<=N;i++){ // dump(pow(p,cnt[i])); // ans += 1-pow(1-p,cnt[i]-1); // } // printf("%.10lf\n", ans); // } // }