## implementation

#include <bits/stdc++.h>
#define REP(i,n) for (int i = 0; (i) < (n); ++(i))
#define REP3(i,m,n) for (int i = (m); (i) < (n); ++(i))
#define ALL(x) begin(x), end(x)
using ll = long long;
using namespace std;

tuple<int, int, int> count_stat(const string & s) {
int n = s.length();
int w = 0, l = 0, q = 0;
REP (x, n) {
switch (s[x]) {
case 'W': case 'w': ++ w; break;
case 'L': case 'l': ++ l; break;
case '?': ++ q; break;
default: break;
}
}
return make_tuple(w, l, q);
}
bool check_stat(const string & s) {
int w, l; tie(w, l, ignore) = count_stat(s);
int k = (s.length() - 1) / 2;
return (w <= k) and (l <= k);
}

int main() {
while (true) {
// input
int n; cin >> n;
if (n == 0) break;
int m; cin >> m;
vector<string> a(n, string(n, '?'));
REP (z, n) a[z][z] = '-';
REP (i, m) {
int x, y; cin >> x >> y;
-- x; -- y;
a[x][y] = 'W';
a[y][x] = 'L';
}
cerr << "n = " << n << endl;
cerr << "m = " << m << endl;

// solve
ll cnt = 0;
function<void (int)> go = [&](int y) {
if (y == n) {
++ cnt;
return;
}
REP3 (z, y, n) {
if (not check_stat(a[y])) {
return;
}
}
int w, l, q; tie(w, l, q) = count_stat(a[y]);
int k = (n - 1) / 2 - w;
assert (0 <= k and k <= q);
REP (s, 1 << q) if (__builtin_popcount(s) == k) {
assert (__builtin_popcount(s) == k);
// update
int i = 0;
REP3 (x, y + 1, n) if (a[y][x] == '?') {
a[x][y] = (s & (1 << i)) ? 'l' : 'w';
++ i;
}
// recur
go(y + 1);
// revert
REP3 (x, y + 1, n) if (a[y][x] == '?') {
a[x][y] = '?';
}
}
};
go(0);

// output
cout << cnt << endl;
cerr << "answer = " << cnt << endl;
}
return 0;
}