#include <bits/stdc++.h>

using namespace std;
using ll = long long;
// #define int ll
using PII = pair<ll, ll>;

#define FOR(i, a, n) for (ll i = (ll)a; i < (ll)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define ALL(x) x.begin(), x.end()

template<typename T> T &chmin(T &a, const T &b) { return a = min(a, b); }
template<typename T> T &chmax(T &a, const T &b) { return a = max(a, b); }
template<typename T> bool IN(T a, T b, T x) { return a<=x&&x<b; }
template<typename T> T ceil(T a, T b) { return a/b + !!(a%b); }

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...));
}
template<typename T,typename V> typename enable_if<is_class<T>::value==0>::type
fill_v(T &t, const V &v) { t=v; }
template<typename T,typename V> typename enable_if<is_class<T>::value!=0>::type
fill_v(T &t, const V &v ) { for(auto &e:t) fill_v(e,v); }

template<class S,class T>
ostream &operator <<(ostream& out,const pair<S,T>& a) {
    out<<'('<<a.first<<','<<a.second<<')'; return out;
}
template<class T>
ostream &operator <<(ostream& out,const vector<T>& a){
    out<<'[';
    for(const T &i: a) out<<i<<',';
    out<<']';
    return out;
}
template<class T>
ostream &operator <<(ostream& out, const set<T>& a) {
    out<<'{';
    for(const T &i: a) out<<i<<',';
    out<<'}';
    return out;
}
template<class T, class S>
ostream &operator <<(ostream& out, const map<T,S>& a) {
    out<<'{';
    for(auto &i: a) out<<i<<',';
    out<<'}';
    return out;
}

int dx[] = {0, 1, 0, -1}, dy[] = {1, 0, -1, 0}; // DRUL
const int INF = 1<<30;
const ll LLINF = 1LL<<60;
const ll MOD = 1000000007;

ll ans;
int n, m;

pair<int,int> next(int x, int y) {
    if(x == n-1) return make_pair(y+2, y+1);
    return make_pair(x+1, y);
}

void dfs(int x, int y, int win, vector<vector<int>> &table) {
    // cout << "x=" << x << " y=" << y << " win=" << win << endl;
    // REP(i, n) cout << table[i] << endl;
    if(y == n-2 && x == n-1) {
        if(table[y][x] == 0 && (win == n/2 || win == n/2-1)) {
            ans++;
            // REP(i, n) cout << table[i] << endl;
            // cout << endl;
            // cout << "plus" << endl;
        } else if(table[y][x] != 0 && win+(table[y][x]==1) == n/2) {
            // REP(i, n) cout << table[i] << endl;
            // cout << endl;
            ans++;
        }
        return;
    }

    int nx, ny, nwin = win;
    tie(nx, ny) = next(x, y);
    if(ny != y) {
        nwin = 0;
        REP(i, ny) nwin += table[ny][i]==1?1:0;
    }

    if(table[y][x] != 0) {
        // cout << "a" << endl;
        if(ny != y) {
            if(win+(table[y][x]==1) == n/2) dfs(nx, ny, nwin, table);
        } else {
            if(win+(table[y][x]==1) <= n/2) dfs(nx, ny, win+(table[y][x]==1), table);
        }
    }
    else {
        // cout << "b" << endl;
        table[y][x] = 1;
        table[x][y] = -1;
        if(ny != y) {
            // cout << x << " " << y << " " << win << " " << nwin << endl;
            if(win+1 == n/2) dfs(nx, ny, nwin, table);
        } else {
            if(win+1 <= n/2) dfs(nx, ny, win+1, table);
        }
        table[y][x] = -1;
        table[x][y] = 1;
        if(ny != y) {
            if(win == n/2) dfs(nx, ny, nwin, table);
        } else {
            if(win <= n/2) dfs(nx, ny, win, table);
        }
        table[x][y] = table[y][x] = 0;
    }
}

signed main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    while(1) {
        cin >> n;
        if(!n) break;
        cin >> m;
        vector<vector<int>> table(n, vector<int>(n));
        REP(i, m) {
            ll x, y;
            cin >> x >> y;
            x--, y--;
            table[x][y] = 1;
            table[y][x] = -1;
        }

        ans = 0;
        dfs(1, 0, 0, table);
        // cerr << "ans=";
        cout << ans << endl;
    }

    return 0;
}



Measured memory_bytes: 3168