#include #include using namespace std; #define SZ(x) (int) (x).size() #define REP(i, n) for(int i = 0; i < (n); i++) #define FOR(i, a, b) for(auto i = (a); i < (b); i++) #define For(i, a, b, c) \ for(auto i = (a); i != (b); i += (c)) #define REPR(i, n) for(auto i = (n) -1; i >= 0; i--) #define ALL(s) (s).begin(), (s).end() #define so(V) sort(ALL(V)) #define rev(V) reverse(ALL(V)) #define uni(v) v.erase(unique(ALL(v)), (v).end()) #define eb emplace_back typedef unsigned long long ull; typedef long long ll; typedef vector vi; typedef vector vll; typedef vector vb; typedef vector vvi; typedef vector vvll; typedef pair PI; typedef pair PL; const double EPS = 1e-6; const int MOD = 1e9 + 7; const int INF = (1 << 30); const ll LINF = 1e18; const double math_PI = acos(-1); template vector make_v(size_t a) { return vector(a); } template auto make_v(size_t a, Ts... ts) { return vector(ts...))>( a, make_v(ts...)); } template typename enable_if::value == 0>::type fill_v( T& t, const V& v) { t = v; } template typename enable_if::value != 0>::type fill_v( T& t, const V& v) { for(auto& e: t) fill_v(e, v); } template bool chmax(T& a, const T& b) { if(a < b) { a = b; return true; } return false; } template bool chmin(T& a, const T& b) { if(a > b) { a = b; return true; } return false; } template istream& operator>>(istream& is, pair& p) { cin >> p.first >> p.second; return is; } template istream& operator>>(istream& is, vector& vec) { for(T& x: vec) is >> x; return is; } template string join(vector& vec, string splitter) { stringstream ss; REP(i, SZ(vec)) { if(i != 0) ss << splitter; ss << vec[i]; } return ss.str(); } template ostream& operator<<(ostream& os, vector& vec) { os << join(vec, " "); return os; } using namespace atcoder; using mint = modint998244353; struct S { mint value; int size; }; using F = ll; S op(S a, S b) { return { a.value + b.value, a.size + b.size }; } S e() { return { mint(0), 0 }; } S mapping(F f, S x) { return { x.value + f * x.size, x.size }; } F composition(F f, F g) { return f + g; } F id() { return 0; } int main() { cin.tie(nullptr); ios::sync_with_stdio(false); int N, M; cin >> N >> M; vector fact(N + 2); fact[0] = mint(1); fact[1] = mint(1); FOR(i, 2, N + 2) { fact[i] = fact[i - 1] * i; } vi A(N, -1); set SE; REP(i, N) SE.insert(i); REP(i, M) { int P, K; cin >> P >> K; P--; K--; A[K] = P; SE.erase(P); } fenwick_tree fw(N); mint ans = 0; REP(i, N) { if(A[i] != -1) { ans += fw.sum(A[i] + 1, N); fw.add(A[i], 1); } } REP(i, N) { fw.add(i, -fw.sum(i, i + 1)); } int rest = N - M; ans *= fact[rest]; if(rest >= 2) ans += (mint(rest) * mint(rest - 1) / 2).pow(2) * fact[rest - 2]; lazy_segtree seg( vector(rest, { mint(0), 1 })); vi R; for(auto s: SE) { R.push_back(s); } if(rest >= 1) { REP(i, N) { if(A[i] == -1) { ans += seg.all_prod().value * fact[rest - 1]; } else { auto it = upper_bound(ALL(R), A[i]); seg.apply(0, it - R.begin(), 1); } } REP(i, rest) { seg.set(i, { mint(0), 1 }); } REPR(i, N) { if(A[i] == -1) { ans += seg.all_prod().value * fact[rest - 1]; } else { auto it = lower_bound(ALL(R), A[i]); seg.apply(it - R.begin(), rest, 1); } } } cout << ans.val() << endl; return 0; }