#include <bits/stdc++.h>
using namespace std;
using LL = long long;

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }


// std::vector Declaration
template<typename T>
vector<T> make_v(size_t a) { return vector<T>(a); }
template<typename T,typename... Ts>
auto make_v(size_t a,Ts... ts) {
    return vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));
}

// std::vector Initialization
template<typename T>
void fill_all(T& arr, const T& v) { arr = v; }
template<typename T, typename U>
void fill_all(T& arr, const U& v) { for (auto& i : arr) fill_all(i, v); }

// std::vector Debug
template<typename T>
ostream& operator<<(ostream& os, const vector<T>& v) {
    os << "[";
    bool a = 1;
    for (auto e : v ) {
        os << (a ? "" : " "); 
        os << e;
        a = 0;
    }
    os << "]";
    return os;
}

// std::pair Debug
template<typename T, typename U>
ostream& operator<<(ostream& os, const pair<T, U>& p) {
    os << "(" << p.first << " " << p.second << ")";
    return os;
}

// std::set Debug
template<typename T>
ostream& operator<<(ostream& os, const set<T>& st) {
    os << "{";
    bool a = 1;
    for (auto e : st) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "}";
    return os;
}

// std::multiset Debug
template<typename T>
ostream& operator<<(ostream& os, const multiset<T>& st) {
    os << "{";
    bool a = 1;
    for (auto e : st) {
        os << (a ? "" : " ");
        os << e;
        a = 0;
    }
    os << "}";
    return os;
}

// std::map Debug
template<typename T, typename U>
ostream& operator<<(ostream& os, const map<T, U>& mp) {
    os << "{";
    bool a = 1;
    for (auto e : mp) {
        os << (a ? "" : " ");
        os << e.first << ":" << e.second;
        a = 0;
    }
    os << "}";
    return os;
}

// std::tuple Debug
template<int N, class Tuple>
void out(ostream& os, const Tuple& t){}
template<int N, class Tuple, class H, class ...Ts>
void out(ostream& os, const Tuple& t) {
    if (N) os << " ";
    os << get<N>(t);
    out<N+1,Tuple,Ts...>(os, t);
}
template<class ...Ts>
ostream& operator<<(ostream& os, const tuple<Ts...>& t) {
    os << "(";
    out<0,tuple<Ts...>,Ts...>(os, t);
    os << ")";
    return os;
}

// Debug
#define DUMP(x) cerr<<#x<<" = "<<(x)<<endl


struct edge { int to, cost; };
ostream& operator<<(ostream& os, const edge& e) {
    os << "(" << e.to << ", " << e.cost << ")";
    return os;
}

const LL LINF = 1LL<<60;
const int IINF = 1<<30;
const LL MOD = 1e9+7;

bool check(auto& s, int i, int j) {
    // cout << "check" << endl;
    // for (auto v : s) {
    //     DUMP(v);
    // }
    // DUMP(i);
    // DUMP(j);
    // cerr << endl;
    int n = s.size();
    int sum = 0;
    for (int k = 0; k <= j; ++k) {
        sum += s[i][k];
    }
    return n-1-j >= abs(sum);
}

int dfs(auto& s, const auto& t, int i, int j)
{
    // cout << "dfs" << endl;
    // for (auto v : s) {
    //     DUMP(v);
    // }
    // DUMP(i);
    // DUMP(j);
    // cerr << endl;

    int n = s.size();
    if (i == n) {
        return 1;
    }
    if (j == n) {
        return dfs(s, t, i+1, 0);
    }
    if (i >= j) {
        return dfs(s, t, i, j+1);
    }

    if (t[i][j] != 0)
    {
        s[i][j] = t[i][j];
        s[j][i] = -t[i][j];
        if (!check(s, i, j)) {
            return 0;
        }
        return dfs(s, t, i, j+1);
    }
    else
    {
        int ret = 0;
        for (auto k : { -1, 1 }) {
            s[i][j] = k;
            s[j][i] = -k;
            if (!check(s, i, j)) {
                continue;
            }
            ret += dfs(s, t, i, j+1);
        }

        return ret;
    }
}

int main()
{
    vector<int> ns, ms;
    vector<vector<int>> xs, ys;
    while (true) {
        int n; cin >> n;
        if (n == 0) break;
        ns.push_back(n);
        int m; cin >> m;
        ms.push_back(m);
        vector<int> x(m), y(m);
        for (int i = 0; i < m; ++i) {
            cin >> x[i] >> y[i];
            --x[i]; --y[i];
        }
        xs.push_back(x);
        ys.push_back(y);
    }

    for (int k = 0; k < ns.size(); ++k) {
        int n = ns[k], m = ms[k];
        auto x = xs[k], y = ys[k];

        auto s = make_v<int>(n, n),
             t = make_v<int>(n, n);
        for (int i = 0; i < m; ++i) {
            t[x[i]][y[i]] =  1;
            t[y[i]][x[i]] = -1;
        }
        // for (auto v : t) {
        //     DUMP(v);
        // }

        cout << dfs(s, t, 0, 1) << endl;
    }

    return 0;
}



Measured memory_bytes: 3132