This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#define wiwihorz
#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#pragma loop-opt(on)
#define rep(i, a, b) for(int i = a; i <= b; i++)
#define rrep(i, a, b) for(int i = b; i >= a; i--)
#define all(x) x.begin(), x.end()
#define ceil(a, b) ((a + b - 1) / (b))
#define INF 1000000000000000000
#define MOD 998244353
#define eps (1e-9)
using namespace std;
#define int long long int
#define lld long double
#define pii pair<int, int>
#define random mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count())
#ifdef wiwihorz
#define print(a...) kout("[" + string(#a) + "] = ", a)
void vprint(auto L, auto R) {while(L < R) cerr << *L << " \n"[next(L) == R], ++L;}
void kout() { cerr << endl; }
template<class T1, class ... T2> void kout(T1 a, T2 ... e) { cerr << a << " ", kout(e...); }
#else
#define print(...) 0
#define vprint(...) 0
#endif
namespace solver {
	int n, m, cur;
	vector<vector<int>> mp;
	vector<pii> es;
	set<int> s;
	void init_(int _n, int _m) {
		n = _n, m = _m;
		s.clear();
		es.clear();
	}
	void add_edge(int a, int b) {
		es.push_back({a, b});
	}
	int solve() {
		int ans = 0;
		vector<int> a(n, 0), id(n + 1, 0);
		rep(i, 1, n) a[i - 1] = i;
		do {
			rep(i, 0, n - 1) id[a[i]] = i + 1;
			int msk = 0;
			rep(i, 0, m - 1) {
				pii cur = es[i];
				if(id[cur.first] < id[cur.second]) {
					msk |= ((int) 1 << i );
				}
			}
			if(s.find(msk) == s.end()) {
				ans = (ans + __builtin_popcount(msk)) % MOD;
				s.insert(msk);
			}
		} while(next_permutation(all(a)));
		return ans;
	} 
};
using namespace solver;
signed main() {
	ios::sync_with_stdio(false), cin.tie(0);
	int n, m; cin >> n >> m;
	init_(n, m);
	rep(i, 1, m) {
		int a, b; cin >> a >> b;
		add_edge(a, b);
	}
	cout << solve() << "\n";
	return 0;	
}
Compilation message (stderr)
amusementpark.cpp:4: warning: ignoring '#pragma loop ' [-Wunknown-pragmas]
    4 | #pragma loop-opt(on)
      | 
amusementpark.cpp:24:13: warning: use of 'auto' in parameter declaration only available with '-fconcepts-ts'
   24 | void vprint(auto L, auto R) {while(L < R) cerr << *L << " \n"[next(L) == R], ++L;}
      |             ^~~~
amusementpark.cpp:24:21: warning: use of 'auto' in parameter declaration only available with '-fconcepts-ts'
   24 | void vprint(auto L, auto R) {while(L < R) cerr << *L << " \n"[next(L) == R], ++L;}
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