#include <bits/stdc++.h>
#define ll long long
#define pii pair<int, int>
#define endl '\n'
using namespace std;
const int BLOCK_SZ = 350;
const int MAX_N = 1e5 + 1;
vector<int> graph[MAX_N];
bool mark[MAX_N];
vector<pii> paths[MAX_N];
int from[MAX_N], dp[MAX_N];
void pre_comp(int v)
{
vector<int> cur(1, v);
from[v] = 0;
for (int u : graph[v])
for (pii pth : paths[u])
{
from[pth.second] = max(from[pth.second], pth.first + 1);
if (!mark[pth.second])
{
cur.push_back(pth.second);
mark[pth.second] = true;
}
}
for (int u : cur)
paths[v].push_back({from[u], u});
for (int u : cur)
{
mark[u] = false;
from[u] = -1;
}
sort(paths[v].begin(), paths[v].end(), greater<pii>());
while (paths[v].size() > BLOCK_SZ)
paths[v].pop_back();
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
int N, M, Q;
cin >> N >> M >> Q;
fill_n(&from[0], N, -1);
for (int i = 0; i < M; i++)
{
int a, b;
cin >> a >> b;
--a;
--b;
graph[b].push_back(a);
}
for (int v = 0; v < N; v++)
pre_comp(v);
while (Q--)
{
int t, y;
cin >> t >> y;
--t;
vector<int> cs(y);
for (int i = 0; i < y; i++)
{
cin >> cs[i];
--cs[i];
mark[cs[i]] = true;
}
if (y >= BLOCK_SZ)
{
for (int v = 0; v <= t; v++)
{
dp[v] = mark[v] ? -1 : 0;
for (int u : graph[v])
if (dp[u] != -1)
dp[v] = max(dp[v], dp[u] + 1);
}
cout << dp[t] << endl;
}
else
{
bool ok = false;
for (pii pth : paths[t])
{
if (!mark[pth.second])
{
cout << pth.first << endl;
ok = true;
break;
}
}
if (!ok)
cout << -1 << endl;
}
for (int c : cs)
mark[c] = false;
}
}
