#include <iostream>
#include <vector>
#include <cstring>
#include <string>
#include <iomanip>
#include <algorithm>
#include <fstream>
#include <cmath>
#include <unordered_set>
#include <set>
#include <unordered_map>
#include <map>
#define ll long long
#define X first
#define Y second
#define endl '\n'
using namespace std;
void speed()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
}
int n, m, q;
const int MAXN = 100100;
vector<int> v[MAXN];
vector<pair<int, int>> d[MAXN];
int sd[MAXN];
const int sq = 320;
int mx[MAXN];
void read()
{
cin >> n >> m >> q;
for (int i = 1; i <= n; i++)
mx[i] = -1;
for (int i = 0; i < m; i++)
{
int x, y;
cin >> x >> y;
v[y].push_back(x);
}
}
bool cmp(pair<int, int> x, pair<int, int> y)
{
if (x.X != y.X)
return x.X > y.X;
return x.Y < y.Y;
}
void dfs(int beg)
{
vector<int> nbb = {beg};
mx[beg] = 0;
for (int nb : v[beg])
{
if (d[nb].empty())
dfs(nb);
for (auto x : d[nb])
{
nbb.push_back(x.Y);
mx[x.Y] = max(mx[x.Y], x.X+1);
}
}
sort(nbb.begin(), nbb.end());
d[beg].push_back({mx[nbb[0]], nbb[0]});
mx[nbb[0]] = -1;
for (int i = 1; i < nbb.size(); i++)
{
if (nbb[i] != nbb[i - 1])
{
d[beg].push_back({mx[nbb[i]], nbb[i]});
mx[nbb[i]] = -1;
}
}
sort(d[beg].begin(), d[beg].end(),cmp);
while (d[beg].size() > sq)
d[beg].pop_back();
}
int used[MAXN];
bool ne[MAXN];
int dp[MAXN];
void DFS(int beg)
{
used[beg] = 1;
if (!ne[beg])
{
dp[beg] = 0;
}
else
{
dp[beg] = -1;
}
for (int nb : v[beg])
{
if (!used[nb])
DFS(nb);
if (dp[nb] != -1)
dp[beg] = max(dp[beg], dp[nb] + 1);
}
}
int big(int beg)
{
for (int i = 1; i <= n; i++)
{
used[i] = 0;
dp[i] = -1;
}
DFS(beg);
return dp[beg];
}
signed main()
{
// speed();
read();
for (int i = 1; i <= n; i++)
{
if (d[i].empty())
dfs(i);
}
while (q--)
{
int beg, y;
cin >> beg >> y;
vector<int> ban;
for (int i = 0; i < y; i++)
{
int x;
cin >> x;
ne[x] = 1;
ban.push_back(x);
}
if (y < sq)
{
int p = 0;
while (p < d[beg].size() && ne[d[beg][p].Y])
p++;
if (p == d[beg].size())
cout << -1 << endl;
else
cout << d[beg][p].X << endl;
}
else
{
cout << big(beg) << endl;
}
for (int x : ban)
{
ne[x] = 0;
}
}
return 0;
}
