#include <bits/stdc++.h>
#define mod 998244353 
#define ll long long
using namespace std;
const int N=5005;
int n,m,k,s,t,sz[N];
ll f[N][N],g[N];
vector<int> e[N];
void dfs(int u,int fa){
	sz[u]=1;f[u][0]=1;
	for (int &v:e[u]){
		if (v==fa) continue;
		dfs(v,u);
		memset(g,0,sizeof(g));
		for (int i=min(sz[u],m);i>=0;--i)
			for (int j=0;j<=sz[v];++j){
				g[i]=(g[i]+f[u][i]*f[v][j])%mod;//断开
				if (i+j+1<=m) g[max(i,j+1)]=(g[max(i,j+1)]+f[u][i]*f[v][j])%mod;//不断开
			}
		sz[u]+=sz[v];
		for (int i=0;i<=min(sz[u],m);++i) f[u][i]=g[i];
	}
}
int main(){
	cin>>n>>m;
	for (int i=1;i<n;++i){
		cin>>s>>t;
		e[s].push_back(t);
		e[t].push_back(s);
	}
	dfs(1,0);
	ll ans=0;
	for (int i=0;i<=m;++i) ans=(ans+f[1][i])%mod;
	cout<<ans<<"\n";
}