#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;

typedef modint998244353 mint;
typedef long long ll;

//defmodfact
const int COMinitMAX = 500;
mint fact[COMinitMAX+1], factinv[COMinitMAX+1];

void modfact(){
	fact[0] = 1;
	for (int i=1; i<=COMinitMAX; i++){
		fact[i] = fact[i-1] * i;
	}
	factinv[COMinitMAX] = fact[COMinitMAX].inv();
	for (int i=COMinitMAX-1; i>=0; i--){
		factinv[i] = factinv[i+1] * (i+1);
	}
}

mint cmb(int a, int b){
	if (a<b || b<0) return mint(0);
	return fact[a]*factinv[b]*factinv[a-b];
}
//--------


int main(){
	modfact();
	int n, m;
	cin >> n >> m;

	if (m < n*(n-1)/2 - n){
		cout << 0 << endl;
		return 0;
	}

	mint inv2 = mint(2).inv();
	vector<vector<mint>> dp(n+1, vector<mint>(n+1));
	dp[0][0] = 1;
	for (int i=0; i<n+1; i++){
		for (int j=0; j<n+1; j++){
			if (i+1 <= n) dp[i+1][j] += dp[i][j];
			for (int k=2; k<=min(n-i, n-j+1); k++){
				dp[i+k][j+k-1] += cmb(n-i-1, k-1) * dp[i][j] * fact[k] * inv2;
			}
			for (int k=5; k<=min(n-i, n-j); k++){
				dp[i+k][j+k] += cmb(n-i-1, k-1) * dp[i][j] * fact[k-1] * inv2;
			}
		}
	}

	if (n*(n-1)/2-m <= n){
		cout << dp[n][n*(n-1)/2-m].val() << endl;
	}else{
		cout << 0 << endl;
	}

}