#include #pragma GCC optimize("Ofast") #pragma GCC optimize("unroll-loops") using namespace std; using std::cout; using std::cin; using std::endl; using ll=long long; using ld=long double; ll ILL=2167167167167167167; const int INF=2100000000; const int mod=998244353; #define rep(i,a,b) for (ll i=a;i using _pq = priority_queue, greater>; template ll LB(vector &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();} template ll UB(vector &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();} 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 void So(vector &v) {sort(v.begin(),v.end());} template void Sore(vector &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});} void yneos(bool a){if(a) cout<<"Yes\n"; else cout<<"No\n";} template void vec_out(vector &p){for(int i=0;i<(int)(p.size());i++){if(i) cout<<" ";cout< T vec_min(vector &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmin(ans,x);return ans;} template T vec_max(vector &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmax(ans,x);return ans;} template T vec_sum(vector &a){assert(!a.empty());T ans=a[0]-a[0];for(auto &x:a) ans+=x;return ans;} int pop_count(long long a){int res=0;while(a){res+=(a&1),a>>=1;}return res;} namespace po167{ struct combination{ int upper; long long MOD; std::vector fact; std::vector rev; std::vector fact_rev; combination(int max,long long mod):upper(max),MOD(mod),fact(max+1),rev(max+1),fact_rev(max+1){ for(long long i=0;i<=max;i++){ if(i<2){ fact[i]=1; fact_rev[i]=1; rev[i]=1; continue; } fact[i]=(fact[i-1]*i)%mod; rev[i]=mod-((mod/i)*rev[mod%i])%mod; fact_rev[i]=(fact_rev[i-1]*rev[i])%mod; } } long long Comb(int x,int y){ assert(upper>=x); if (x=x); if (x struct segment_tree{ int _n,size; std::vector seg; int ceil_pow2(int a){ int b=1; while(a>b){ b<<=1; } return b; } void update(int k){seg[k]=op(seg[k*2],seg[k*2+1]);}; segment_tree(int n) :_n(n){ size=ceil_pow2(n); seg=std::vector(size*2,e()); } segment_tree(std::vector &p) :_n((int) p.size()){ size=ceil_pow2(_n); seg=std::vector(size*2,e()); for(int i=0;i<_n;i++) seg[i+size]=p[i]; for(int i=size-1;i>0;i--) update(i); } void set(int ind,T val){ assert(0<=ind&&ind<_n); ind+=size; seg[ind]=val; while(ind!=1){ ind>>=1; update(ind); } } void addl(int ind,T val){ set(ind,op(get(ind),val)); } void addr(int ind,T val){ set(ind,op(val,get(ind))); } T get(int ind){ assert(0<=ind&&ind<_n); return seg[ind+size]; } T query(int l,int r){ assert(0<=l&&l<=r&&r<=_n); T l_val=e(); T r_val=e(); l+=size,r+=size; while(l>=1; l>>=1; } return op(l_val,r_val); } template int max_right(int l) { return max_right(l, [](T x) { return f(x); }); } template int max_right(int l, F f) { assert(0<=l&&l<=_n); assert(f(e())); if(f(query(l,_n))) return _n; T val=e(); l+=size; while(true){ while(l%2==0) l>>=1; if(!f(op(val,seg[l]))){ while(l int min_left(int r) { return min_left(r, [](T x) { return f(x); }); } template int min_left(int r, F f) { assert(0 <= r && r <= _n); assert(f(e())); if (r == 0) return 0; r += size; T sm = e(); do { r--; while (r > 1 && (r % 2)) r >>= 1; if (!f(op(seg[r], sm))) { while (r < size) { r = (2 * r + 1); if (f(op(seg[r], sm))) { sm = op(seg[r], sm); r--; } } return r + 1 - size; } sm = op(seg[r], sm); } while ((r & -r) != r); return 0; } }; } using po167::segment_tree; using F= ll; F op(F a,F b){return a+b;} F e(){return 0;} int target; bool f(F x){ return (x%target==0); } void solve(); // oddloop int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int t=1; //cin>>t; rep(i,0,t) solve(); } void solve(){ ll N,M; cin>>N>>M; combination table(N,mod); vector p(N+1,1),q(N,-1); rep(i,0,M){ ll a,b; cin>>a>>b; a--,b--; q[b]=a; p[a]=0; } rep(i,0,N) p[i+1]+=p[i]; ll ans=((N-M)*(N-M-1))/2; ans%=mod; ans=(ans*table.fact_rev[2])%mod; ll X=0,Y=N-M; segment_tree seg(N); rep(i,0,N){ if(q[i]==-1){ X++,Y--; continue; } ll B=p[q[i]],A=N-M-B; ll tmp=(A*X)%mod; tmp=(tmp+(B*Y))%mod; tmp=(tmp*table.rev[N-M])%mod; ans=(ans+tmp)%mod; ans=(ans+seg.query(q[i],N))%mod; seg.set(q[i],1); } ans=(ans*table.fact[N-M])%mod; cout<<(ans+mod)%mod<<"\n"; }