#include <iostream>
#include <stdio.h>
#include <math.h>
#include <string.h>
#include <time.h>
#include <stdlib.h>
#include <string>
#include <bitset>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <algorithm>
#include <sstream>
#include <stack>
#include <iomanip>
#include <assert.h>
using namespace std;
#define pb push_back
#define mp make_pair
typedef pair<int,int> pii;
typedef long long ll;
typedef double ld;
typedef vector<int> vi;
#define fi first
#define se second
#define fe first
#define FO(x) {freopen(#x".in","r",stdin);freopen(#x".out","w",stdout);}
#define Edg int M=0,fst[SZ],vb[SZ],nxt[SZ];void ad_de(int a,int b){++M;nxt[M]=fst[a];fst[a]=M;vb[M]=b;}void adde(int a,int b){ad_de(a,b);ad_de(b,a);}
#define Edgc int M=0,fst[SZ],vb[SZ],nxt[SZ],vc[SZ];void ad_de(int a,int b,int c){++M;nxt[M]=fst[a];fst[a]=M;vb[M]=b;vc[M]=c;}void adde(int a,int b,int c){ad_de(a,b,c);ad_de(b,a,c);}
#define es(x,e) (int e=fst[x];e;e=nxt[e])
#define esb(x,e,b) (int e=fst[x],b=vb[e];e;e=nxt[e],b=vb[e])
const int MOD=1e9+7;
#define SZ 666666
ll qp(ll a,ll b)
{
    ll x=1; a%=MOD;
    while(b)
    {
        if(b&1) x=x*a%MOD;
        a=a*a%MOD;b>>=1;
    }
    return x;
}
int T,n,m;Edg
int fa[SZ];
void dfs(int x,int f=0)
{
    fa[x]=f;
    for esb(x,e,b) if(b!=f)
        dfs(b,x);
}
int st[SZ],mk[SZ];
void sol()
{
    scanf("%d%d",&n,&m); M=0;
    for(int i=1;i<=n;++i) fst[i]=mk[i]=0;
    for(int i=1;i<n;++i)
    {
        int a,b;
        scanf("%d%d",&a,&b);
        adde(a,b);
    }
    if(m==1)
    {
        puts("1");
        return;
    }
    dfs(1); int sn=0;
    for(int j=m;j!=1;j=fa[j]) st[++sn]=j;
    st[++sn]=1;
    reverse(st+1,st+1+sn);
    for(int i=1;i<=sn;++i) mk[st[i]]=1;
    ll ans=1;
    for(int i=1;i<sn;++i)
    {
        int o=0;
        for esb(st[i],e,b) ++o;
        ans=ans*qp(o,MOD-2)%MOD;
    }
    for(int oo=1;oo<sn;++oo)
    {
        ll og=1;
        for(int x=1;x<sn;++x)
        {
            int o=0,w=0;
            for esb(st[x],e,b) ++o,w+=b!=st[x-1]&&b!=st[x+1];
            if(x!=oo)
                og=og*qp(o,MOD-2)%MOD;
            else og=og*qp(o-1,MOD-2)%MOD*w%MOD*qp(o,MOD-2)%MOD;
        }
        (ans+=og)%=MOD;
    }
    ans=(ans%MOD+MOD)%MOD;
    printf("%d\n",int(ans));
}
int main()
{
    scanf("%d",&T);
    while(T--) sol();
}