#include <bits/stdc++.h>
using namespace std;
/*{{{*/  //template
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rrep(i,n) for(int i=(n)-1;i>=0;i--)
constexpr int INF = numeric_limits<int>::max()/2;
constexpr long long LINF = numeric_limits<long long>::max()/3;
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define all(v) (v).begin(),(v).end()
#define sz(x) (int)(x).size()
#define debug(x) cerr<<#x<<":"<<x<<endl
#define debug2(x,y) cerr<<#x<<","<<#y":"<<x<<","<<y<<endl
//struct fin{ fin(){ cin.tie(0); ios::sync_with_stdio(false); } } fin_;
struct Double{ double d; explicit Double(double x) : d(x){} };
ostream& operator<<(ostream& os,const Double x){ os << fixed << setprecision(20) << x.d; return os; }
template<typename T> ostream& operator<<(ostream& os,const vector<T>& vec){ os << "["; for(const auto& v : vec){ os << v << ","; } os << "]"; return os; }
template<typename T,typename U> ostream& operator<<(ostream& os, const map<T,U>& mp){ os << "{"; for(auto& p : mp){ os << p << ","; } os << "}"; return os; }
template<typename T,typename U> ostream& operator<<(ostream& os,const pair<T,U>& p){ os << "(" << p.first << ","<< p.second <<")"; return os; }
template<typename T> ostream& operator<<(ostream& os,const set<T>& st){ os<<"{"; for(T v:st) os<<v<<","; os <<"}"; return os; }
template<typename T,typename U> inline void chmax(T &x,U y){ if(y>x) x = y; }
template<typename T,typename U> inline void chmin(T &x,U y){ if(y<x) x = y; }
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
ll gcd(ll a,ll b){ if(b==0) return a; else return gcd(b,a%b); }
//constexpr double eps = 1e-14; 
constexpr double eps = 1e-10; 
constexpr ll mod = 1e9+7;
const int dx[]={1,0,-1,0} ,dy[] = {0,1,0,-1};
/*}}}*/

struct SCC{/*{{{*/
    int V; // # of node
    vector<vector<int>> G,rG;
    vector<int> vs,cmp; // vs:行きかけ順序の並び cmp:どの集合に属するか?
    vector<bool> used;

    SCC(){}
    SCC(int v){ init(v); }

    void init(int v){
        V = v;
        G.assign(V,vector<int>());
        rG.assign(V,vector<int>());
        vs.clear();
        cmp.resize(V);
    }

    void add_edge(int from,int to){
        G[from].emplace_back(to);
        rG[to].emplace_back(from);
    }

    void dfs(int v){
        used[v] = true;
        for(const int& u : G[v]) if(!used[u]) dfs(u);
        vs.push_back(v);
    }

    // @args k 何番目の成分か?
    void rdfs(int v,int k){
        used[v] = true;
        cmp[v] = k;
        for(const int& u : rG[v]) if(!used[u]) rdfs(u,k);
    }

    // @return 強連結成分分解した後の成分の数
    int scc(){
        used.assign(V,false);
        for(int v=0;v<V;v++) if(!used[v]) dfs(v);
        used.assign(V,false);
        int k=0;
        for(int i=vs.size()-1;i>=0;i--){
            if(!used[vs[i]]) rdfs(vs[i],k++);
        }
        return k;
    }

    bool is_same(int i,int j){ return cmp[i] == cmp[j]; }
};/*}}}*/

void solve(int N){
    vector<double> p(N);
    vector<vector<int>> G(N);
    rep(i,N){
        cin >> p[i];
        int m; cin >> m;
        G[i].resize(m);
        rep(j,m){
            cin >> G[i][j];
            G[i][j]--;
        }
    }

    SCC graph(N);
    rep(u,N){
        for(int v:G[u]){
            graph.add_edge(u,v);
        }
    }
    int K = graph.scc();

    /* cerr << "K = " << K << endl; */
    /* cerr << "cmp = " << graph.cmp << endl; */

    vector<double> p2(K,1);
    for(int i=0;i<N;i++) p2[graph.cmp[i]] *= p[i];
    /* cerr << "p2 = " << p2 << endl; */

    vector<set<int>> rg(N);
    rep(u,N){
        int uu = graph.cmp[u];
        for(int v:G[u]){
            int vv = graph.cmp[v];
            if(uu==vv) continue;
            rg[vv].insert(uu);
        }
    }


    double ans = 1.0;
    for(int i=0;i<K;i++){
        if(rg[i].size() == 0){
            ans *= 1.0-p2[i];
        }
    }
    cout << Double(ans) << endl;
}

int main(){
    int N;
    while(1){
        cin >> N;
        if(N==0) break;
        solve(N);
    }
}



Measured memory_bytes: 3400