#include <iostream>
#include <vector>
using namespace std;
const int maxN = 100'000;
const int rt = 100;
const int INF = 1'000'000'000;
vector<bool> occ(1+maxN, 0);
vector<pair<int, int> > distances[1+maxN];
void combine(int i, int j) //combine arrays i and j, store in i.
{
// cerr << "combine " << i << ' ' << j << '\n';
vector< pair<int, int> > res;
int u = 0;
int v = 0;
while(1)
{
if(u < int(distances[i].size()) && occ[distances[i][u].second])
{
u++;
continue;
}
if(v < int(distances[j].size()) && occ[distances[j][v].second])
{
v++;
continue;
}
if(u >= int(distances[i].size()) && v >= int(distances[j].size()))
{
break;
}
// cerr << "o: " << distances[i].size() << ' ' << distances[j].size() << ' ' << u << ' ' << v << '\n';
if(u >= int(distances[i].size()))
{
occ[distances[j][v].second] = 1;
res.push_back(distances[j][v]);
// cerr << "A " << distances[j][v].first << ' ' << distances[j][v].second << '\n';
v++;
}
else if(v >= int(distances[j].size()))
{
occ[distances[i][u].second] = 1;
res.push_back(distances[i][u]);
// cerr << "B " << distances[i][u].first << ' ' << distances[i][u].second << '\n';
u++;
}
else if(distances[i][u] > distances[j][v])
{
occ[distances[i][u].second] = 1;
res.push_back(distances[i][u]);
// cerr << "C " << distances[i][u].first << ' ' << distances[i][u].second << '\n';
u++;
}
else
{
occ[distances[j][v].second] = 1;
res.push_back(distances[j][v]);
// cerr << "D " << distances[j][v].first << ' ' << distances[j][v].second << '\n';
// cerr << v << ' ' << distances[j].size() << '\n';
v++;
}
}
// cerr << "while loop done\n";
distances[i] = res;
while(int(distances[i].size()) > rt)
distances[i].pop_back();
for(auto r:res) occ[r.second] = 0;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int N, M, Q;
cin >> N >> M >> Q;
vector<int> edge[1+N];
vector<int> rev_edge[1+N];
for(int j = 1; j <= M; j++)
{
int u, v;
cin >> u >> v;
edge[u].push_back(v);
rev_edge[v].push_back(u);
}
//(dist, source), sorted decreasingly by dist
for(int i = 1; i <= N; i++)
{
distances[i].push_back(make_pair(0, i));
for(int j: rev_edge[i])
{
combine(i, j);
}
for(int u = 0; u < int(distances[i].size()); u++)
distances[i][u].first++;
}
for(int i = 1; i <= N; i++)
{
for(int u = 0; u < int(distances[i].size()); u++)
distances[i][u].first--;
}
// for(int i = 1; i <= N; i++)
// {
// cerr << "\n\n" << "node " << i << ": \n";
// for(auto p: distances[i]) cerr << p.first << ' ' << p.second << '\n';
// }
for(int q = 1; q <= Q; q++)
{
int T, Y;
cin >> T >> Y;
vector<int> C(Y);
for(int i = 0; i < Y; i++) cin >> C[i];
if(Y >= rt)
{
vector<bool> excluded(1+N, 0);
for(int c:C) excluded[c] = 1;
vector<int> maxdist(1+N, -INF);
for(int i = 1; i <= T; i++)
{
if(!excluded[i]) maxdist[i] = 0;
for(int j: rev_edge[i]) maxdist[i] = max(maxdist[i], 1 + maxdist[j]);
}
if(maxdist[T] < 0) maxdist[T] = -1;
cout << maxdist[T] << '\n';
}
else
{
for(int c:C) occ[c] = 1;
int res = -1;
for(pair<int, int> q: distances[T])
{
if(!occ[q.second])
res = max(res, q.first);
}
for(int c:C) occ[c] = 0;
cout << res << '\n';
}
}
}
