#include <bits/stdc++.h>
using namespace std;
template<typename T>
using V = vector<T>;
using vi = V<int>;
using vb = V<bool>;
using pi = pair<int,int>;
#define F0R(i,n) for (int i = 0; i < n;i++)
#define FOR(i, j, n) for(int i = j; i < n;i++)
#define ckmin(x,y) x = min(x,y)
#define f first
#define s second
using ll = long long;
constexpr int MOD = 998244353;
V<int> vis;
V<V<int>> g;
bool dfs(int x) {
if (vis[x] == 1) return false;
vis[x] = 1;
for (auto y : g[x]) {
if (vis[y] == 2) continue;
if (!dfs(y)) return false;
}
vis[x] = 2;
return true;
}
int main() {
ios_base::sync_with_stdio(false); cin.tie(nullptr);
int n, m; cin >> n >> m;
V<pi> edges(m);
set<pi> exists;
F0R(i, m) {
int x, y; cin >> x >> y;
x--;
y--;
edges[i] = {x,y};
exists.insert({x,y});
exists.insert({y,x});
}
ll ans = 0;
vi perm(n); // Height of I
F0R(i, n)
perm[i] = i;
do {
int cost = 0;
for (auto [a,b] : edges) {
if (perm[a] > perm[b]) cost++;
}
bool pos = true;
V<pi> check;
F0R(i, n) {
check.emplace_back(perm[i],i);
}
std::sort(check.begin(), check.end());
F0R(i, n - 1) {
int a = check[i].s;
for (int j = i + 1; j < n; ++j) {
int b = check[j].s;
if (exists.count({a,b})) break;
if (a > b) pos = false;
}
}
if (pos)
ans += cost;
ans %= MOD;
} while (std::next_permutation(perm.begin(), perm.end()));
cout << ans;
return 0;
}
