RT，代码：

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
const int N=5010;
int qpow(int a,int n)
{
	int ans=1;
	while(n)
	{
		if(n&1) ans=(long long)ans*a%998244353;
		a=(long long)a*a%998244353;
		n>>=1;
	}
	return ans;
}
int f[N],p[N],inv[N];
int C(int n,int m) {return (long long)p[n]*inv[m]%998244353*inv[n-m]%998244353;}
int main()
{
	int n,m;
	scanf("%d%d",&n,&m);
	p[0]=inv[0]=1;
	for(int i=1;i<=n;i++)
	{
		p[i]=(long long)p[i-1]*i%998244353;
		inv[i]=qpow(p[i],998244351);
	}
	f[0]=1;
	for(int i=0;(1<<i)<=m;i++)
		for(int j=m;j>=0;j--)
			for(int k=1;2*k*(1<<i)<=j;k++)
				if(j-2*k*(1<<i)>=0)
				{ 
					f[j]+=(long long)f[j-2*k*(1<<i)]*C(n,2*k)%998244353;
					f[j]%=998244353;
				}
	printf("%d",f[m]);
	return 0;
}

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