#include <bits/stdc++.h>

#pragma GCC optimize("O3")
#pragma GCC target("tune=native")
#pragma GCC target("avx")
// #pragma GCC target("avx2")
#pragma GCC optimize("unroll-loops")

using namespace std;


using i64 = __int128;

const i64 MOD = 1e9+7;

const i64 INF = i64(1e18)+MOD;

template <typename T = i64>
struct Range{
    struct iterator{
        T value;
        const T step, last;
        const T& operator*(){return value;}
        iterator(T value, T step, T last) :
            value(step < static_cast<T>(0) ? max(last, value) : min(last, value)),
            step(step),
            last(last)
        {
        }
        iterator operator++(){value = step < static_cast<T>(0) ? max(value + step, last) : min(value + step, last); return *this;}
        bool operator!=(const iterator& x){return value != x.value;}
    };
    const T start, last, step;

    Range(const T start, const T last, const T step = static_cast<T>(1)) :
        start(start),
        last(last),
        step(step)
    {
    }

    Range(const T last) :
        start(0),
        last(last),
        step(1)
    {
    }

    iterator begin(){return iterator(start, step, last);}
    iterator end(){return iterator(last, step, last);}
};

template <typename F>
struct FixPoint{
    const F _f;
    FixPoint(F&& f) : _f(forward<F>(f)){}

    template<typename... Types>
    decltype(auto) operator()(Types&&... args) const{
        return _f(*this, forward<Types>(args)...);
    }
};

template <typename F>
static decltype(auto) makeRec(F&& f){
    return FixPoint<F>(forward<F>(f));
}

template <typename T, T Value = T()>
vector<T> makeVector(size_t x){
    return vector<T>(x, T(Value));
}

template <typename T, T Value = T(), typename... Types>
auto makeVector(size_t x, Types... args){
    return vector<decltype(makeVector<T, Value>(args...))>(x, makeVector<T, Value>(args...));
}

template <typename T = i64>
bool chmax(T& a, T b){
    if(a < b){
        a = b;
        return true;
    }
    return false;
}

template <typename T = i64>
bool chmin(T& a, T b){
    if(a > b){
        a = b;
        return true;
    }
    return false;
}

#define dump(x) fprintf(stderr, "line =%4d, name =%7s , ", __LINE__, #x); clog << "value = " << x << endl;

#define vecdump(x) fprintf(stderr, "line =%4d, name =%7s\n", __LINE__, #x); _dump_macro(x);

void _dump(int, string& x){
    clog << x << endl;
}

template <typename T>
void _dump(bool, T& x){
    clog << x << " ";
}

template <typename T, typename U = typename T::iterator>
void _dump(int, T& x){

    for(auto& elm : x)
        _dump(0, elm);

    clog << endl;
}

template <typename T>
void _dump_macro(T& x){
    _dump(0, x);
}

void _input(int, string& x){
    cin >> x;
}

template <typename T>
void _input(bool, T& x){
    cin >> x;
}

template <typename T, typename U = typename T::iterator>
void _input(int, T& x){

    for(auto& elm : x)
        _input(0, elm);
}

template <typename T>
void input_single(T& x){
    _input(0, x);
}

auto input(){}

template <typename T, typename... Types>
void input(T& value, Types&&... args){
    input_single(value);
    input(forward<Types>(args)...);
};

void _pararell_input(size_t){}

template <typename T, typename... Types>
void _pararell_input(size_t index, T& value, Types&&... args){
    input(value[index]);
    _pararell_input(index, forward<Types>(args)...);
}

template <typename... Types>
void pararell_input(size_t count, Types&&... args){
    for(const auto& i : Range<>(count))
        _pararell_input(i, forward<Types>(args)...);
}

vector<int> scc(vector<vector<int>>& edges){
    int n = edges.size();
    vector<vector<int>> rev(n);

    for(int i = 0; i < n; ++i)
        for(auto& x : edges[i])
            rev[x].emplace_back(i);

    vector<i64> dfs_num(n, -1);
    vector<i64> flag(n, 0);
    int num = 0;
    function<void(int)> dfs = [&](int pos){
        flag[pos] = 1;
        for(auto& xx : edges[pos])
            if(!flag[xx]){
                dfs(xx);
        }
        dfs_num[pos] = num++;
    };

    for(int i = 0; i < n; ++i)
        if(!flag[i])
            dfs(i);

    vector<int> dfs_inv(n);
    for(int i = 0; i < n; ++i)
        dfs_inv[n - 1 - dfs_num[i]] = i;

    num = 0;

    vector<int> scc_vec(n, -1);

    function<void(int)> rdfs = [&](int pos){
        scc_vec[pos] = num;
        for(auto t : rev[pos])
            if(scc_vec[t] == -1)
                rdfs(t);
    };

    for(int i = 0; i < n; ++i)
        if(scc_vec[dfs_inv[i]] == -1){
            rdfs(dfs_inv[i]);
            ++num;
        }

    return scc_vec;
}


bool solve(){

    int n;
    input(n);
    if(!n)
        return false;
    vector<double> p(n);
    vector<vector<int>> v(n);
    for(int i = 0; i < n; ++i){
        int m;
        input(p[i], m);
        for(int j = 0; j < m; ++j){
            int to;
            input(to);
            v[i].emplace_back(--to);
        }
    }
    auto sc = scc(v);
    int k = *max_element(sc.begin(), sc.end()) + 1;
    bitset<100> bs;
    for(int i = 0; i < n; ++i)
        for(auto& x : v[i])
            if(sc[i] != sc[x])
                bs.set(sc[x]);
    double ans = 1.0;
    for(int i = 0; i < k; ++i){
        if(bs[i])
            continue;
        double per = 0.0;
        for(int j = 0; j < n; ++j)
            if(sc[j] == i)
                per += (1.0 - per) * (1.0 - p[j]);
        ans *= per;
    }
    cout << ans << endl;

    return true;
}

signed main(){

    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);

    while(solve());

}



Measured memory_bytes: 3352