#include<bits/stdc++.h>

using namespace std;
#define INFS (1LL<<28)
#define DEKAI 1000000007
#define INF 1000000007
//#define MOD 1000000007
#define lp(i,n) for(int i=0;i<n;i++)
#define lps(i,n) for(int i=1;i<=n;i++)
#define all(c) begin(c), end(c)

//#define int long long 

namespace {
	#define __DECLARE__(C)    \
	    template <typename T> \
	std::ostream &operator<<(std::ostream &, const C<T> &);

	#define __DECLAREM__(C)               \
	    template <typename T, typename U> \
	std::ostream &operator<<(std::ostream &, const C<T, U> &);

	__DECLARE__(std::vector)
	__DECLARE__(std::deque)
	__DECLARE__(std::set)
	__DECLARE__(std::stack)
	__DECLARE__(std::queue)
	__DECLARE__(std::priority_queue)
	__DECLARE__(std::unordered_set)
	__DECLAREM__(std::map)
	__DECLAREM__(std::unordered_map)

	template <typename T, typename U>
	std::ostream &operator<<(std::ostream &, const std::pair<T, U> &);
	template <typename... T>
	std::ostream &operator<<(std::ostream &, const std::tuple<T...> &);
	template <typename T, std::size_t N>
	std::ostream &operator<<(std::ostream &, const std::array<T, N> &);

	template <typename Tuple, std::size_t N>
	struct __TuplePrinter__ {
		static void print(std::ostream &os, const Tuple &t) {
			__TuplePrinter__<Tuple, N - 1>::print(os, t);
			os << ", " << std::get<N - 1>(t);
		}
	};

	template <typename Tuple>
	struct __TuplePrinter__<Tuple, 1> {
		static void print(std::ostream &os, const Tuple &t) { os << std::get<0>(t); }
	};

	template <typename... T>
	std::ostream &operator<<(std::ostream &os, const std::tuple<T...> &t) {
		os << '(';
		__TuplePrinter__<decltype(t), sizeof...(T)>::print(os, t);
		os << ')';
		return os;
	}

	template <typename T, typename U>
	std::ostream &operator<<(std::ostream &os, const std::pair<T, U> &v) {
		return os << '(' << v.first << ", " << v.second << ')';
	}

	#define __INNER__                             \
	os << '[';                                \
	for (auto it = begin(c); it != end(c);) { \
		os << *it;                            \
		os << (++it != end(c) ? ", " : "");   \
	}                                         \
	return os << ']';

	template <typename T, std::size_t N>
	std::ostream &operator<<(std::ostream &os, const std::array<T, N> &c) {
		__INNER__
	}

	#define __DEFINE__(C)                                           \
	    template <typename T>                                       \
	std::ostream &operator<<(std::ostream &os, const C<T> &c) { \
		__INNER__                                               \
	}

	#define __DEFINEM__(C)                                             \
	    template <typename T, typename U>                              \
	std::ostream &operator<<(std::ostream &os, const C<T, U> &c) { \
		__INNER__                                                  \
	}

	#define __DEFINEW__(C, M1, M2)                                  \
	    template <typename T>                                       \
	std::ostream &operator<<(std::ostream &os, const C<T> &c) { \
		std::deque<T> v;                                        \
		for (auto d = c; !d.empty(); d.pop()) v.M1(d.M2());     \
			return os << v;                                         \
	}

	__DEFINE__(std::vector)
	__DEFINE__(std::deque)
	__DEFINE__(std::set)
	__DEFINEW__(std::stack, push_front, top)
	__DEFINEW__(std::queue, push_back, front)
	__DEFINEW__(std::priority_queue, push_front, top)
	__DEFINE__(std::unordered_set)
	__DEFINEM__(std::map)
	__DEFINEM__(std::unordered_map)
}

#define pii pair<int,int>
#define ll long long
inline ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
inline ll lcm(ll a, ll b) { return a / gcd(a, b) * b; }

// modint 
template <signed M, unsigned T>
struct mod_int {
	constexpr static signed MODULO = M;
	constexpr static unsigned TABLE_SIZE = T;

	signed x;

	mod_int() : x(0) {}

	mod_int(long long y) : x(static_cast<signed>(y >= 0 ? y % MODULO : MODULO - (-y) % MODULO)) {}

	mod_int(int y) : x(y >= 0 ? y % MODULO : MODULO - (-y) % MODULO) {}

	mod_int &operator+=(const mod_int &rhs) {
		if ((x += rhs.x) >= MODULO) x -= MODULO;
		return *this;
	}

	mod_int &operator-=(const mod_int &rhs) {
		if ((x += MODULO - rhs.x) >= MODULO) x -= MODULO;
		return *this;
	}

	mod_int &operator*=(const mod_int &rhs) {
		x = static_cast<signed>(1LL * x * rhs.x % MODULO);
		return *this;
	}

	mod_int &operator/=(const mod_int &rhs) {
		x = static_cast<signed>((1LL * x * rhs.inv().x) % MODULO);
		return *this;
	}

	mod_int operator-() const { return mod_int(-x); }

	mod_int operator+(const mod_int &rhs) const { return mod_int(*this) += rhs; }

	mod_int operator-(const mod_int &rhs) const { return mod_int(*this) -= rhs; }

	mod_int operator*(const mod_int &rhs) const { return mod_int(*this) *= rhs; }

	mod_int operator/(const mod_int &rhs) const { return mod_int(*this) /= rhs; }

	bool operator<(const mod_int &rhs) const { return x < rhs.x; }

	mod_int inv() const {
		assert(x != 0);
		if (x <= static_cast<signed>(TABLE_SIZE)) {
			if (_inv[1].x == 0) prepare();
			return _inv[x];
		} else {
			signed a = x, b = MODULO, u = 1, v = 0, t;
			while (b) {
				t = a / b;
				a -= t * b;
				std::swap(a, b);
				u -= t * v;
				std::swap(u, v);
			}
			return mod_int(u);
		}
	}

	mod_int pow(long long t) const {
		assert(!(x == 0 && t == 0));
		mod_int e = *this, res = mod_int(1);
		for (; t; e *= e, t >>= 1)
			if (t & 1) res *= e;
		return res;
	}

	mod_int fact() {
		if (_fact[0].x == 0) prepare();
		return _fact[x];
	}

	mod_int inv_fact() {
		if (_fact[0].x == 0) prepare();
		return _inv_fact[x];
	}

	mod_int choose(mod_int y) {
		assert(y.x <= x);
		return this->fact() * y.inv_fact() * mod_int(x - y.x).inv_fact();
	}

	static mod_int _inv[TABLE_SIZE + 1];

	static mod_int _fact[TABLE_SIZE + 1];

	static mod_int _inv_fact[TABLE_SIZE + 1];

	static void prepare() {
		_inv[1] = 1;
		for (int i = 2; i <= (int)TABLE_SIZE; ++i) {
			_inv[i] = 1LL * _inv[MODULO % i].x * (MODULO - MODULO / i) % MODULO;
		}
		_fact[0] = 1;
		for (unsigned i = 1; i <= TABLE_SIZE; ++i) {
			_fact[i] = _fact[i - 1] * int(i);
		}
		_inv_fact[TABLE_SIZE] = _fact[TABLE_SIZE].inv();
		for (int i = (int)TABLE_SIZE - 1; i >= 0; --i) {
			_inv_fact[i] = _inv_fact[i + 1] * (i + 1);
		}
	}
};

template <int M, unsigned F>
std::ostream &operator<<(std::ostream &os, const mod_int<M, F> &rhs) {
	return os << rhs.x;
}

template <int M, unsigned F>
std::istream &operator>>(std::istream &is, mod_int<M, F> &rhs) {
	long long s;
	is >> s;
	rhs = mod_int<M, F>(s);
	return is;
}

template <int M, unsigned F>
mod_int<M, F> mod_int<M, F>::_inv[TABLE_SIZE + 1];

template <int M, unsigned F>
mod_int<M, F> mod_int<M, F>::_fact[TABLE_SIZE + 1];

template <int M, unsigned F>
mod_int<M, F> mod_int<M, F>::_inv_fact[TABLE_SIZE + 1];

template <int M, unsigned F>
bool operator==(const mod_int<M, F> &lhs, const mod_int<M, F> &rhs) {
	return lhs.x == rhs.x;
}

template <int M, unsigned F>
bool operator!=(const mod_int<M, F> &lhs, const mod_int<M, F> &rhs) {
	return !(lhs == rhs);
}

const int MF = 1000010;
const int MOD = 1000000007;

using mint = mod_int<MOD, MF>;

mint binom(int n, int r) { return (r < 0 || r > n || n < 0) ? 0 : mint(n).choose(r); }

mint fact(int n) { return mint(n).fact(); }

mint inv_fact(int n) { return mint(n).inv_fact(); }
const ll mod = 1000000007;
const int MAX_N = 10000;  // 400MB
// const int MAX_N = 1024; // 4MB
// nCr % mod

//#define int long long
#define double long double 

inline ll gcds(ll a, ll b) { return b ? gcds(b, a % b) : a; }
inline ll lcms(ll a, ll b) { return a / gcd(a, b) * b; }

#define RK 200000000000
#define LK 300000000000
#define PL 400000000000
#define MI 500000000000
#define KA 600000000000


using Weight = int;
using Flow = int;
struct Edge {
    int src, dst;
    Weight weight;
    Flow cap;
    Edge() : src(0), dst(0), weight(0) {}
    Edge(int s, int d, Weight w) : src(s), dst(d), weight(w) {}
};
using Edges = std::vector<Edge>;
using Graph = std::vector<Edges>;
using Array = std::vector<Weight>;
using Matrix = std::vector<Array>;

void add_edge(Graph &g, int a, int b, Weight w = 1) {
    g[a].emplace_back(a, b, w);
    g[b].emplace_back(b, a, w);
}
void add_arc(Graph &g, int a, int b, Weight w = 1) { g[a].emplace_back(a, b, w); }

std::vector<int> kosaraju(const Graph &g) {
    int n = g.size(), sz = 0;
    Graph rg(n);
    std::vector<int> stk, cmp(n, -1), added(n), visited(n), ord(n);
    for (auto &es : g) {
        for (auto e : es) {
            std::swap(e.src, e.dst);
            rg[e.src].emplace_back(e);
        }
        sz += es.size();
    }
    stk.resize(n + sz);
    sz = 0;
    for (int i = 0; i < n; i++) {
        if (visited[i]) continue;
        int s = 0;
        stk[s++] = i;
        while (s != 0) {
            int v = stk[s - 1];
            visited[v] = true;
            bool pushed = false;
            for (auto &e : g[v]) {
                int dst = e.dst;
                if (!visited[dst]) {
                    stk[s++] = dst;
                    pushed = true;
                }
            }
            if (pushed) continue;
            int t = stk[s - 1];
            if (!added[t]) {
                added[t] = true;
                ord[n - ++sz] = t;
            }
            --s;
        }
    }
    int k = 0;
    for (int &u : ord) {
        if (cmp[u] != -1) continue;
        int s = 0;
        stk[s++] = u;
        while (s != 0) {
            int v = stk[--s];
            cmp[v] = k;
            for (auto &e : rg[v]) {
                int d = e.dst;
                if (cmp[d] == -1) stk[s++] = d;
            }
        }
        ++k;
    }
    return cmp;
}


signed main(){
	while(1){
		int n;
		cin>>n;
		Graph g(n);
		if(n==0)break;

		vector<bool> check(n,false);
		vector<double> p(n);
		vector<vector<int>> revg(n);

		lp(i,n){
			cin>>p[i];
			int m;
			cin>>m;
			lp(j,m){
				int a;
				cin>>a;
				revg[a-1].push_back(i);
				add_arc(g,i,a-1);
				check[a-1]=true;
			}
		}

		vector<int> cmp=kosaraju(g);
		int maxin=0;
		lp(i,cmp.size()){
			maxin=max(cmp[i],maxin);
		}
		vector<bool> checks(maxin+1,true);
		lp(i,n){
			lp(j,revg[i].size()){
				int now = i;
				int to=revg[i][j];
				if(cmp[now]!=cmp[to]){
					checks[cmp[now]]=false;
				}
			}
		}



		double ans=1;
		lp(i,checks.size()){
			double base=1;
			if(checks[i]){
				lp(j,cmp.size()){
					if(i==cmp[j]){
						base*=p[j];
					}
				}
				ans*=1-base;
			}
		}
		cout<<fixed<<setprecision(15)<<ans<<endl;
	}
	return 0;
}



Measured memory_bytes: 15344