//Let's join Kaede Takagaki Fan Club !! #pragma GCC optimize("Ofast") #pragma GCC optimize("unroll-loops") #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include //#include //#include #include #include #include #include #include #include #include #include //#include //#include //#include //#include //#include //#include using namespace std; //using namespace atcoder; #define int long long //#define L __int128 typedef long long ll; typedef pair P; typedef pair P1; typedef pair P2; #define pu push #define pb push_back #define eb emplace_back #define mp make_pair #define eps 1e-7 #define INF 1000000000 #define a first #define b second #define fi first #define sc second #define rng(i,a,b) for(int i=(int)(a);i<(int)(b);i++) #define rep(i,x) for(int i=0;i bool chmax(t&a,u b){if(a bool chmin(t&a,u b){if(b using vc=vector; template ostream& operator<<(ostream& os,const pair& p){ return os<<"{"< ostream& operator<<(ostream& os,const vc& v){ os<<"{"; for(auto e:v)os<> 30)) * 0xbf58476d1ce4e5b9; x = (x ^ (x >> 27)) * 0x94d049bb133111eb; return x ^ (x >> 31); } size_t operator()(uint64_t x) const { static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count(); return splitmix64(x + FIXED_RANDOM); } //don't make x negative! size_t operator()(pair x)const{ return operator()(uint64_t(x.first)<<32|x.second); } }; //unordered_set -> dtype, null_type //unordered_map -> dtype(key), dtype(value) using namespace __gnu_pbds; template using hash_table=gp_hash_table; template void o(const T &a,bool space=false){ cout << a << (space?' ':'\n'); } //ios::sync_with_stdio(false); const ll mod = 998244353; //const ll mod = 1000000007; mt19937_64 mt(chrono::steady_clock::now().time_since_epoch().count()); struct modular{ ll v; modular(ll vv=0){s(vv%mod+mod);} modular& s(ll vv){ v=vv>=1; } return res; } modular inv()const{return pow(mod-2);} friend modular operator+(ll x,const modular&y){ return modular(x)+y; } friend modular operator-(ll x,const modular&y){ return modular(x)-y; } friend modular operator*(ll x,const modular&y){ return modular(x)*y; } friend modular operator/(ll x,const modular&y){ return modular(x)/y; } friend ostream& operator<<(ostream&os,const modular&m){ return os<>(istream&is,modular&m){ ll x;is>>x; m=modular(x); return is; } bool operator<(const modular&r)const{return v0){ if(n&1) res=res*x%mod; x=x*x%mod; n>>=1; } return res; } #define _sz 1005 modular F[_sz],R[_sz]; void make(){ F[0] = 1; for(int i=1;i<_sz;i++) F[i] = F[i-1] * i; R[_sz-1] = F[_sz-1].pow(mod-2); for(int i=_sz-2;i>=0;i--) R[i] = R[i+1] * (i+1); } modular C(int a,int b){ if(b < 0 || a < b) return modular(); return F[a]*R[b]*R[a-b]; } /*int dst(P p, P q){ return (p.a-q.a)*(p.a-q.a)+(p.b-q.b)*(p.b-q.b); }*/ /*template void add_inplace(t &a, t b){ if(a.size() < b.size()) swap(a, b); for(int i=0;i= mod) a[i] -= mod; } return ; }*/ /*template void ov(const vc&a){ if(a.empty()) return; rep(i, a.size()) cout << a[i] << (i+1==a.size()?'\n':' '); }*/ //o(ans?"Yes":"No"); modular dp[305][305]; void solve(){ int n,m;cin>>n>>m; m=n*(n-1)/2-m; if(m>n){ o(0); return; } make(); dp[0][0]=1; repn(i,n){ rep(j,i+1){ //i, j repn(x, i){ if(j-x+1>=0)dp[i][j]+=dp[i-x][j-x+1]*C(i-1,x-1)*(x==1?1:F[x]/2); if(x>4){ if(j-x>=0)dp[i][j]+=dp[i-x][j-x]*C(i-1,x-1)*F[x-1]/2; } } } } o(dp[n][m]); } signed main(){ cin.tie(0); ios::sync_with_stdio(0); cout<> t; while(t--) solve(); }