#include <bits/stdc++.h>
using namespace std;
inline void setup()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
int n, m, q, a, b, s[100000];
const int block_size = 320;
vector<int> g[100000];
vector<pair<int, int>> f[100000], v;
bool banned[100000];
int main()
{
setup();
cin >> n >> m >> q;
while (m--)
{
cin >> a >> b;
g[b - 1].push_back(a - 1);
}
fill_n(s, n, -1);
for (int i = 0; i < n; ++i)
{
v = {{0, i}};
for (auto &j : g[i])
{
for (auto &k : f[j])
{
v.push_back({k.first + 1, k.second});
}
}
sort(v.begin(), v.end(), greater<pair<int, int>>());
for (int j = 0; j < v.size() && f[i].size() < block_size; ++j)
{
if (s[v[j].second] != i)
{
f[i].push_back(v[j]);
s[v[j].second] = i;
}
}
}
while (q--)
{
cin >> a >> b;
v.clear();
v.resize(b);
a--;
for (int i = 0; i < v.size(); ++i)
{
cin >> v[i].first;
v[i].first --;
banned[v[i].first] = true;
}
if (b < block_size)
{
b = -1;
for (auto & i : f[a])
{
if (!banned[i.second])
{
b = i.first;
break;
}
}
}
else
{
b = -1;
fill_n(s, n, -1);
s[a] = 0;
for (int i = a; i >= 0; --i)
{
if (s[i] != -1)
{
if (!banned[i])
{
b = max(b, s[i]);
}
for (auto & j : g[i])
{
s[j] = max(s[j], s[i] + 1);
}
}
}
}
for (int i = 0; i < v.size(); ++i)
{
banned[v[i].first] = false;
}
cout << b << '\n';
}
return 0;
}
