#include "bits/stdc++.h"
using namespace std;
#ifdef _DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

//#define int long long
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(c) begin(c),end(c)
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = (int)(1e9) + 7;
template<class T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T &a, const T &b) { if (a > b) { a = b; return true; } return false; }

using Weight = int;
using Flow = int;
struct Edge {
	int s, d; Weight w; Flow c;
	Edge() {};
	Edge(int s, int d, Weight w = 1) : s(s), d(d), w(w), c(w) {};
	bool operator<(const Edge &e)const { return w < e.w; }
};
using Edges = vector<Edge>;
using Graph = vector<Edges>;
using Array = vector<Weight>;
using Matrix = vector<Array>;

inline ostream &operator<<(ostream &os, const Edge &e) { return (os << '(' << e.s << ", " << e.d << ", " << e.w << ')'); }

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 s, int d, Weight w = 1) { g[s].emplace_back(s, d, w); }

//テヲツ慊ェテヲツ篠「テァツエツ「, テヲツ篠「テァツエツ「テ、ツクツュ, テヲツ篠「テァツエツ「テヲツクツ?
enum { WHITE, GRAY, BLACK };

//テ・ツ債佚、ツクツ?・ツァツ凝ァツつケテヲツ慊?ァツ淞ュテァツオツ古ィツキツッ(ティツイツ?ゥツ鳴嘉ィツキツッテ」ツ?ェテ」ツ??
//Dijkstra O((E+V)logV)
//dist: テ・ツァツ凝ァツつケテ」ツ?凝」ツつ嘉・ツ青?ゥツ?づァツつケテ」ツ?セテ」ツ?ァテ」ツ?ョテヲツ慊?ァツ淞ュティツキツ敕ゥツ崢「
//テヲツ按サテ」ツつ甘・ツ?、: テヲツ慊?ァツ淞ュテァツオツ古ィツキツッテヲツ慊ィテ」ツ?ョティツヲツェテゥツ?づァツつケ(テヲツ?ケテ」ツ?ッ-1)
vector<int> dijkstra(const Graph &g, int s, vector<Weight> &dist) {
	int n = g.size();
	vector<int> color(n, WHITE); color[s] = GRAY;
	vector<int> prev(n, -1);
	dist.assign(n, INF); dist[s] = 0;
	using State = tuple<Weight, int, int>; //テ・ツァツ凝ァツつケテ」ツ?凝」ツつ嘉」ツ?ョテヲツ慊?ァツ淞ュティツキツ敕ゥツ崢「 テ・ツュツ?ティツヲツェ
	priority_queue<State, vector<State>, greater<State>> pq; pq.emplace(0, s, -1);
	while (pq.size()) {
		Weight d; int v, u; tie(d, v, u) = pq.top(); pq.pop(); //distテ」ツ?古ヲツ慊?・ツーツ湘」ツ?ィテ」ツ?ェテ」ツつ鬼tateテ」ツつ津・ツ渉姪」ツつ甘・ツ?コテ」ツ??
		if (dist[v] < d)continue; //テ」ツ?凖」ツ?ァテ」ツ?ォテヲツ慊?ァツ淞ュテ」ツ?ァテ」ツ?ェテ」ツ?妥」ツつ古」ツ?ーテァツ?。ティツヲツ?
		color[v] = BLACK; prev[v] = u;
		for (auto &e : g[v]) {
			if (color[e.d] == BLACK)continue;
			if (dist[e.d] > dist[v] + e.w) {
				dist[e.d] = dist[v] + e.w;
				pq.emplace(dist[e.d], e.d, v);
				color[e.d] = GRAY;
			}
		}
	}
	return prev;
}

//テ・ツ?ィテァツつケテ・ツッツセテゥツ鳴禿ヲツ慊?ァツ淞ュテァツオツ古ィツキツッ 
void all_pairs_shortest_paths_by_dijkstra(const Graph &g, Matrix &dists) {
	int n = g.size();
	dists.resize(n);
	for (int i = 0; i < n; i++)
		dijkstra(g, i, dists[i]);
}

//テァツエツ?ゥツ崢?・ツ青暗」ツδ?」ツδシテ」ツつソテヲツァツ凝ゥツ??
struct UnionFind {
	vector<int> parent;
	int size;
	UnionFind(int n) :parent(n, -1), size(n) {}
	bool unite(int x, int y) {
		x = root(x); y = root(y);
		if (x == y)return false;
		if (size_of(x) < size_of(y))swap(x, y);
		parent[x] += parent[y]; parent[y] = x; size--;
		return true;
	}
	bool same(int x, int y) { return root(x) == root(y); }
	int root(int x) { return parent[x] < 0 ? x : parent[x] = root(parent[x]); }
	int size_of(int x) { return -parent[root(x)]; }
};

signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout << fixed << setprecision(8);
	for (int N; cin >> N&&N;) {
		vector<double> p(N);
		Graph g(N);
		rep(i, 0, N) {
			cin >> p[i];
			int M; cin >> M;
			rep(j, 0, M) {
				int a; cin >> a;
				add_arc(g, i, a - 1);
			}
		}
		Matrix dists;
		all_pairs_shortest_paths_by_dijkstra(g, dists);
		UnionFind uf(N);
		vector<int> in(N);
		vector<double> pp(N, 1.0);
		rep(i, 0, N)rep(j, 0, N) {
			if (dists[i][j] != INF&&dists[j][i] != INF) {
				uf.unite(i, j);
			}
			else if (dists[i][j] != INF) {
				in[j]++;
			}
			else if (dists[j][i] != INF) {
				in[i]++;
			}
		}
		rep(i, 0, N) {
			pp[uf.root(i)] *= p[i];
		}
		dump(pp);
		vector<bool> f(N);
		double ans = 1;
		rep(i, 0, N) {
			if (in[i]) continue;
			if (f[uf.root(i)])continue;
			f[uf.root(i)] = true;
			ans *= 1 - pp[uf.root(i)];
		}
		cout << ans << endl;
	}
	return 0;
}

Measured memory_bytes: 3396