# include <bits/stdc++.h>
# define pb push_back
using namespace std;
typedef long long LL;
const LL mod = 1e9+7;
vector<int>g[503];
int n, m;
LL dp[503][20003];
inline void scan(int &ret)
{
	char c; ret=0;
	while((c=getchar())<'0'||c>'9');
	while(c>='0'&&c<='9') ret=ret*10+(c-'0'),c=getchar();
}
inline void out(LL x)
{
   if(x>9) out(x/10);
   putchar(x%10+'0');
}
inline void add(LL &a, LL b)
{
    a += b;
    if(a >= mod) a -= mod;
}
inline void pro(LL &a, LL b)
{
    a *= b;
    if(a >= mod) a%=mod;
}
void dfs(int u, int pre)
{
    for(auto v : g[u])
    {
        if(v == pre) continue;
        dfs(v, u);
        for(int i=1; i<=m; ++i)
        {
            LL sum = 0;
            for(int j=i; j<=m; j+=i)
                add(sum, dp[v][j]);
            pro(dp[u][i], sum);
        }
    }
}
int main()
{
    int T, a, b;
    scan(T);
    while(T--)
    {
        scan(n), scan(m);
        for(int i=1; i<=n; ++i) g[i].clear();
        for(int i=1; i<=n; ++i)
            for(int j=1; j<=m; ++j)
            dp[i][j] = 1LL;
        for(int i=1; i<n; ++i)
        {
            scan(a), scan(b);
            g[a].pb(b);
            g[b].pb(a);
        }
        dfs(1, 0);
        LL ans = 0;
        for(int i=1; i<=m; ++i)
            add(ans, dp[1][i]);
        out(ans);
        putchar('\n');
    }
    return 0;
}
--------------------- 
作者：junior19 
来源：CSDN 
原文：https://blog.csdn.net/junior19/article/details/77428019 
版权声明：本文为博主原创文章，转载请附上博文链接！