// بِسْمِ اللَّهِ الرَّحْمَنِ الرَّحِيمِ
// Written by Ilia Rahbar
// #pragma GCC optimize ("O3,no-stack-protector,unroll-loops,fast-math")
// #pragma GCC target ("abm,bmi,bmi2,tbm,avx2")
#include <bits/stdc++.h>
using namespace std;
#define int int64_t
#define sz(x) int(x.size())
#define ai(x) array <int, x>
#define be(x) x.begin(), x.end()
#define pb push_back
#define el '\n'
#define sp ' '
#define fi first
#define se second
const int M = 1e9 + 7, N = 1e6 + 100;
int n, m, q, u, ans, v, vs[N], t, sq = 100, dp[N];
bool av[N];
vector <int> g[N], in;
vector <ai(2)> f[N], uni;
void mrg(vector <ai(2)> &a, vector <ai(2)> &b)
{
uni.clear();
for (int p1 = 0, p2 = 0; p1 < sz(a) || p2 < sz(b); )
{
if (p1 < sz(a))
{
if (p2 < sz(b))
{
if (a[p1][0] > b[p2][0])
uni.pb(a[p1++]);
else
uni.pb(b[p2++]);
}
else
uni.pb(a[p1++]);
}
else
uni.pb(b[p2++]);
}
b.clear();
for (auto [x, y] : uni)
if (!vs[y])
vs[y] = 1, b.pb({x, y});
for (auto [x, y] : uni)
vs[y] = 0;
if (sz(b) > sq)
b.resize(sq);
}
int32_t main()
{
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> m >> q;
while (m--)
cin >> u >> v, g[u].pb(v);
for (int i = 1; i <= n; i++)
f[i].pb({0, i});
for (int i = 1; i <= n; i++)
{
for (int j = 0; j < sz(f[i]); j++)
f[i][j][0]++;
for (auto j : g[i])
mrg(f[i], f[j]);
for (int j = 0; j < sz(f[i]); j++)
f[i][j][0]--;
}
while (q--)
{
cin >> u >> t;
in.clear();
ans = -1;
for (int i = 0; i < t; i++)
cin >> v, in.pb(v), av[v] = 1;
for (auto [x, y] : f[u])
if (!av[y])
{
ans = x;
break;
}
if (t >= sq && ans == -1)
{
fill(dp, dp + u + 1, -M);
for (int i = 1; i <= u; i++)
{
if (!av[i])
dp[i] = max(dp[i], int(0));
for (auto j : g[i])
dp[j] = max(dp[j], dp[i] + 1);
}
ans = dp[u];
}
cout << (ans < 0 ? -1 : ans) << el;
for (auto i : in)
av[i] = 0;
}
}
