#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
const ll N = 1e5 + 5;
const ll mod = 998244353;
const ll inf = LLONG_MAX/3;
#define bit(x,y) ((x >> y) & 1LL)
vector<ll> a[N];
ll id[N],ide[N],sz[N],bc[N],p[N],ch[N],uv[N],sum = 0,rt;
ll ti = 0;
void build(ll x, ll px)
{
p[x] = px;
sz[x] = 1;
for(auto y : a[x])
{
if(y == px) continue;
build(y,x);
sz[x] += sz[y];
if(sz[bc[x]] < sz[y]) bc[x] = y;
}
}
void build2(ll x, ll px)
{
id[x] = ide[x] = ++ti;
if(bc[x])
{
build2(bc[x],x);
ide[x] = ide[bc[x]];
}
for(auto y : a[x])
{
if(y == px || y == bc[x]) continue;
build2(y,x);
ide[x] = ide[y];
}
}
struct segtree
{
ll n;
ll b[N * 4];
ll lz[N * 4];
void build(ll n)
{
this->n = n;
}
void push(ll x, ll l, ll mid, ll r)
{
if(lz[x] == 0) return;
ll x1 = x * 2 + 1;
ll x2 = x1 + 1;
ll sz1 = mid - l + 1;
ll sz2 = r - mid;
b[x1] = sz1 - b[x1];
lz[x1] ^= 1;
b[x2] = sz2 - b[x2];
lz[x2] ^= 1;
lz[x] = 0;
}
void udt(ll l, ll r)
{
udt(0,1,n,l,r);
}
void udt(ll x, ll l, ll r, ll s, ll e)
{
if(s <= l && r <= e)
{
ll sz = r - l + 1;
b[x] = sz - b[x];
lz[x] ^= 1;
return;
}
if(r < s || e < l) return;
ll mid = (l + r) / 2;
push(x,l,mid,r);
udt(x * 2 + 1,l,mid,s,e);
udt(x * 2 + 2,mid + 1,r,s,e);
b[x] = b[x * 2 + 1] + b[x * 2 + 2];
}
ll get(ll l, ll r)
{
l = max(2LL,l);
if(l > r) return 0;
return get(0,1,n,l,r);
}
ll get(ll x, ll l, ll r, ll s, ll e)
{
if(s <= l && r <= e) return b[x];
if(r < s || e < l) return 0;
ll mid = (l + r) / 2;
push(x,l,mid,r);
return get(x * 2 + 1,l,mid,s,e) + get(x * 2 + 2,mid + 1,r,s,e);
}
ll rget()
{
return rget(0,1,n);
}
ll rget(ll x, ll l, ll r)
{
if(l == r) return b[x];
ll mid = (l + r) / 2;
push(x,l,mid,r);
return rget(x * 2 + 1,l,mid);
}
};
segtree f;
void buildval(ll x, ll px)
{
uv[x] = 0;
for(auto y : a[x])
{
if(y == px) continue;
buildval(y,x);
uv[x] += uv[y];
}
if(uv[x] == 0)
{
uv[x] = 1;
}else
{
if(uv[x] % 2 == 0) uv[x] = 2;
else uv[x] = 1;
}
if(x != rt) sum += uv[x];
if(uv[x] == 1) f.udt(id[x],id[x]);
}
void buildchain(ll x, ll chx)
{
ch[x] = chx;
if(bc[x]) buildchain(bc[x],chx);
}
ll get(ll x)
{
ll ans = 0;
while(x != 0)
{
ll c1 = f.get(id[ch[x]],id[x]);
ll c2 = (id[x] - id[ch[x]] + (ch[x] != rt)) - c1;
ans += c1 - c2;
f.udt(id[ch[x]],id[x]);
x = p[ch[x]];
}
return ans;
}
void cle(ll x)
{
while(x != 0)
{
f.udt(id[ch[x]],id[x]);
x = p[ch[x]];
}
}
ll isleaf[N];
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
ll n,q;
cin >> n >> q;
ll i,j;
for(i = 1;i < n;i++)
{
ll u,v;
cin >> u >> v;
a[u].push_back(v);
a[v].push_back(u);
}
for(i = 1;i <= n;i++)
{
if(a[i].size() >= 2) rt = i;
else isleaf[i] = 1;
}
f.build(n);
build(rt,0);
build2(rt,0);
buildval(rt,0);
for(i = 1;i <= n;i++)
{
if(bc[p[i]] == i) continue;
buildchain(i,i);
}
while(q--)
{
ll k;
cin >> k;
ll ans = sum;
vector<pair<ll,ll>> haha;
for(i = 1;i <= k;i++)
{
ll x;
cin >> x;
if(isleaf[x])
{
isleaf[x] = 0;
ans++;
haha.push_back({x,1});
}else
{
ans += get(x) + 1;
haha.push_back({x,0});
}
}
if(f.rget() == 0) cout << ans << "\n";
else cout << -1 << "\n";
while(haha.size() > 0)
{
ll x = haha.back().first;
ll tt = haha.back().second;
haha.pop_back();
if(tt == 0) cle(x);
else isleaf[x] = 1;
}
}
}
