#line 1 "main.cpp" //#pragma GCC target("avx,avx2") //#pragma GCC optimize("O3") //#pragma GCC optimize("unroll-loops") #include #ifdef LOCAL #include #define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__) #else #define debug(...) (static_cast(0)) #endif using namespace std; using ll = long long; using ld = long double; using pll = pair; using pii = pair; using vi = vector; using vvi = vector; using vvvi = vector; using vl = vector; using vvl = vector; using vvvl = vector; using vpii = vector; using vpll = vector; using vs = vector; template using pq = priority_queue, greater>; #define overload4(_1, _2, _3, _4, name, ...) name #define overload3(a,b,c,name,...) name #define rep1(n) for (ll UNUSED_NUMBER = 0; UNUSED_NUMBER < (n); ++UNUSED_NUMBER) #define rep2(i, n) for (ll i = 0; i < (n); ++i) #define rep3(i, a, b) for (ll i = (a); i < (b); ++i) #define rep4(i, a, b, c) for (ll i = (a); i < (b); i += (c)) #define rep(...) overload4(__VA_ARGS__, rep4, rep3, rep2, rep1)(__VA_ARGS__) #define rrep1(n) for(ll i = (n) - 1;i >= 0;i--) #define rrep2(i,n) for(ll i = (n) - 1;i >= 0;i--) #define rrep3(i,a,b) for(ll i = (b) - 1;i >= (a);i--) #define rrep4(i,a,b,c) for(ll i = (a) + ((b)-(a)-1) / (c) * (c);i >= (a);i -= c) #define rrep(...) overload4(__VA_ARGS__, rrep4, rrep3, rrep2, rrep1)(__VA_ARGS__) #define all1(i) begin(i) , end(i) #define all2(i,a) begin(i) , begin(i) + a #define all3(i,a,b) begin(i) + a , begin(i) + b #define all(...) overload3(__VA_ARGS__, all3, all2, all1)(__VA_ARGS__) #define sum(...) accumulate(all(__VA_ARGS__),0LL) template bool chmin(T &a, const T &b){ if(a > b){ a = b; return 1; } else return 0; } template bool chmax(T &a, const T &b){ if(a < b){ a = b; return 1; } else return 0; } template auto min(const T& a){return *min_element(all(a));} template auto max(const T& a){return *max_element(all(a));} template void in(Ts&... t); #define INT(...) int __VA_ARGS__; in(__VA_ARGS__) #define LL(...) ll __VA_ARGS__; in(__VA_ARGS__) #define STR(...) string __VA_ARGS__; in(__VA_ARGS__) #define CHR(...) char __VA_ARGS__; in(__VA_ARGS__) #define DBL(...) double __VA_ARGS__; in(__VA_ARGS__) #define LD(...) ld __VA_ARGS__; in(__VA_ARGS__) #define VEC(type, name, size) vector name(size); in(name) #define VV(type, name, h, w) vector> name(h, vector(w)); in(name) ll intpow(ll a, ll b){ ll ans = 1; while(b){if(b & 1) ans *= a; a *= a; b /= 2;} return ans;} ll modpow(ll a, ll b, ll p){ ll ans = 1; a %= p;if(a < 0) a += p;while(b){ if(b & 1) (ans *= a) %= p; (a *= a) %= p; b /= 2; } return ans; } ll GCD(ll a,ll b) { if(a == 0 || b == 0) return 0; if(a % b == 0) return b; else return GCD(b,a%b);} ll LCM(ll a,ll b) { if(a == 0) return b; if(b == 0) return a;return a / GCD(a,b) * b;} void Yes() {cout << "Yes\n";return;} void No() {cout << "No\n";return;} void YES() {cout << "YES\n";return;} void NO() {cout << "NO\n";return;} namespace IO{ #define VOID(a) decltype(void(a)) struct setting{ setting(){cin.tie(nullptr); ios::sync_with_stdio(false);fixed(cout); cout.precision(12);}} setting; template struct P : P{}; template<> struct P<0>{}; template void i(T& t){ i(t, P<3>{}); } void i(vector::reference t, P<3>){ int a; i(a); t = a; } template auto i(T& t, P<2>) -> VOID(cin >> t){ cin >> t; } template auto i(T& t, P<1>) -> VOID(begin(t)){ for(auto&& x : t) i(x); } template void ituple(T& t, index_sequence){in(get(t)...);} template auto i(T& t, P<0>) -> VOID(tuple_size{}){ituple(t, make_index_sequence::value>{});} #undef VOID } #define unpack(a) (void)initializer_list{(a, 0)...} template void in(Ts&... t){ unpack(IO :: i(t)); } #undef unpack static const double PI = 3.1415926535897932; template struct REC { F f; REC(F &&f_) : f(forward(f_)) {} template auto operator()(Args &&...args) const { return f(*this, forward(args)...); }}; constexpr int mod = 998244353; //constexpr int mod = 1000000007; #line 2 "library/modint/Modint.hpp" template struct Modint{ int x; Modint():x(0) {} Modint(long long y): x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {} Modint &operator += (const Modint &p) { if((x += p.x) >= mod) x -= mod; return *this;} Modint &operator -= (const Modint &p) { if ((x += mod - p.x) >= mod) x -= mod; return *this;} Modint &operator *= (const Modint &p) { x = (int)(1LL * x * p.x % mod); return *this;} Modint &operator /= (const Modint &p) { *this *= p.inverse(); return *this;} Modint operator -() const{return Modint(-x);} Modint operator +(const Modint &p) const {return Modint(*this) += p;} Modint operator -(const Modint &p) const {return Modint(*this) -= p;} Modint operator *(const Modint &p) const {return Modint(*this) *= p;} Modint operator /(const Modint &p) const {return Modint(*this) /= p;} Modint &operator ++() {if(x == mod - 1) x = 0; else x++; return *this;} Modint &operator --() {if(x == 0) x = mod - 1; else x--; return *this;} bool operator == (const Modint &p) const {return x == p.x;} bool operator != (const Modint &p) const {return x != p.x;} Modint inverse() const { int a = x, b = mod, u = 1, v = 0, t; while (b > 0) { t = a / b; swap(a -= t * b, b); swap(u -= t * v, v); } return Modint(u);} Modint pow(long long n) const { Modint ret(1), mul(x); while (n > 0) { if (n & 1) ret *= mul; mul *= mul; n >>= 1; } return ret;} friend ostream &operator<<(ostream &os, const Modint &p) { return os << p.x; } friend istream &operator>>(istream &is, Modint &a) { long long t; is >> t; a = Modint(t); return (is); } int get() const { return x; } static constexpr int get_mod() {return mod;} }; #line 90 "main.cpp" using mint = Modint; using vm = vector; using vvm = vector; using vvvm = vector; #line 2 "library/graph/graph-template.hpp" template struct Edge { int from, to; T cost; Edge() = default; Edge(int _to, T _cost) : from(-1), to(_to), cost(_cost) {} Edge(int _from, int _to, T _cost) : from(_from), to(_to), cost(_cost) {} bool operator < (const Edge &a) const { return cost < a.cost; } bool operator > (const Edge &a) const { return cost > a.cost; } Edge &operator = (const int &x) { to = x; return *this; } operator int() const { return to; } friend ostream operator<<(ostream &os, Edge &edge) { return os << edge.to; } }; template using Edges = vector>; template using Wgraph = vector>; using Ugraph = vector>; Ugraph uinput(int N, int M = -1, bool is_directed = false, int origin = 1) { Ugraph g(N); if (M == -1) M = N - 1; while(M--) { int a,b; cin >> a >> b; a -= origin, b -= origin; g[a].push_back(b); if(!is_directed) g[b].push_back(a); } return g; } template Wgraph winput(int N, int M = -1, bool is_directed = false,int origin = 1) { Wgraph g(N); if (M == -1) M = N - 1; while(M--) { int a,b; T c; cin >> a >> b >> c; a -= origin, b -= origin; g[a].emplace_back(b,c); if(!is_directed) g[b].emplace_back(a,c); } return g; } #line 3 "library/graph/cycledetection.hpp" //自己ループは判定しない template vector> cycleditection(const G &g,bool directed = true) { vector pidx(g.size(),-1),vis(g.size()); vector> cycle; int fin = 0; auto dfs = [&](auto rec,int cur,int pval,int par) -> int { pidx[cur] = pval; vis[cur] = 1; for(auto &dst:g[cur]) { if(fin) return -1; if(!directed && dst == par) continue; if(pidx[dst] == pidx[cur]) { cycle.emplace_back(cur,dst); return dst; } if(vis[dst]) continue; int nx = rec(rec,dst,pval,cur); if(nx != -1) { cycle.emplace_back(cur,dst); if(cur == nx) { fin = 1; return -1; } return nx; } } pidx[cur] = -1; return -1; }; for(int i = 0;i < (int)g.size();i++) { if(vis[i])continue; dfs(dfs,i,i,-1); } if(fin) { reverse(begin(cycle),end(cycle)); return cycle; } return vector> {}; } #line 95 "main.cpp" vector fact, fact_inv; void make_fact(int n){ fact.resize(n+1), fact_inv.resize(n+1); fact[0] = mint(1); rep(i,1,n+1) fact[i] = fact[i-1] * mint(i); fact_inv[n] = fact[n].inverse(); rrep(i,0,n) fact_inv[i] = fact_inv[i+1] * mint(i+1); } mint ncr(int n, int r){ if(n < 0 || r < 0 || n < r) return mint(0); return fact[n] * fact_inv[r] * fact_inv[n-r];} mint npr(int n, int r){ if(n < 0 || r < 0 || n < r) return mint(0); return fact[n] * fact_inv[n-r]; } void solve() { INT(n,m,k); vvi g(n); vi F; vi pos(n,-1); vpii edges; rep(i,k) { INT(u,v); u--,v--; g[u].emplace_back(v); F.emplace_back(u); F.emplace_back(v); edges.emplace_back(u,v); } sort(all(F)); F.erase(unique(all(F)),F.end()); rep(i,F.size()) pos[F[i]] = i; vi chk(F.size()); for(auto &[u,v]:edges) chk[pos[v]] |= 1 << pos[u]; debug(chk); auto C = cycleditection(g); if(!C.empty()) { debug(C); cout << 0 << '\n'; return; } mint tmp = 0; mint ans; rep(i,F.size()) { vm dp(1 << F.size()); if(chk[i] > 0) continue; dp[1 << i] = 1; rep(j,1 << F.size()) { rep(l,F.size()) { if(~j >> l & 1) { if((chk[l] & j) == chk[l]) { //debug(j,l); dp[j + (1 << l)] += dp[j]; } } } } tmp += dp.back(); if(F[i] >= m) ans += dp.back() * ncr(n-1,(int)F.size() - 1) * fact[n-(int)F.size()]; //debug(i,tmp,dp); } int fcnt = 0; rep(i,m,n) { if(pos[i] == -1) fcnt++; } if(F.size() == 0) ans += fact[n-1] * fcnt; else ans += tmp * ncr(n-1,(int)F.size()) * fcnt * npr(n-(int)F.size()-1,n-(int)F.size()-1); cout << ans << '\n'; } int main() { //INT(TT); make_fact(1000100); int TT = 1; while(TT--) solve(); }