// 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, v, t, sq = 400, dp[N];
bool av[N];
vector <int> g[N];
vector <ai(2)> f[N];
map <int, int> s[N];
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++)
{
s[i][i] = 0;
for (auto [x, y] : s[i])
f[i].pb({y, x});
sort(f[i].begin(), f[i].end(), [](ai(2) a, ai(2) b){return a[0] > b[0];});
if (sz(f[i]) > sq)
f[i].resize(sq);
for (auto j : g[i])
for (auto [l, k] : f[i])
s[j][k] = max(s[j][k], l + 1);
}
while (q--)
{
cin >> u >> t;
if (t >= sq)
{
for (int i = 1; i <= u; i++)
av[i] = 1, dp[i] = -M;
for (int i = 0; i < t; i++)
cin >> v, av[v] = 0;
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);
}
cout << (dp[u] < 0 ? -1 : dp[u]) << el;
}
else
{
map <int, bool> mp;
for (int i = 0; i < t; i++)
cin >> v, mp[v] = 1;
for (auto [l, k] : f[u])
{
if (!mp[k])
{
cout << l << el;
goto done;
}
}
cout << -1 << el;
done:;
}
}
}
