#include <iostream>
#include <vector>
#include <algorithm>
inline void speed()
{
std::ios_base::sync_with_stdio(false);
std::cin.tie(0);
std::cout.tie(0);
}
int n, m, q;
const int MAXN = 100100;
std::vector<int> v[MAXN];
std::vector<std::pair<int, int>> d[MAXN];
int sd[MAXN];
const int sq = 200;
int mx[MAXN];
inline void read()
{
std::cin >> n >> m >> q;
int x, y;
for (int i = 0; i < m; i++)
{
std::cin >> x >> y;
v[y].push_back(x);
}
}
inline bool cmp(const std::pair<int, int>&x,const std::pair<int, int>&y)
{
if (x.first != y.first)
return x.first > y.first;
return x.second < y.second;
}
void dfs(int&beg)
{
std::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.second);
mx[x.second] = std::max(mx[x.second], x.first + 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] = std::max(dp[beg], dp[nb] + 1);
}
}
inline int big(int beg)
{
for (int i = 1; i <= n; i++)
used[i] = 0;
DFS(beg);
return dp[beg];
}
signed main()
{
speed();
read();
for (int i = 1; i <= n; i++)
{
if (d[i].empty())
dfs(i);
}
std::vector<int> ban;
int x;
int beg, y;
while (q--)
{
ban.clear();
std::cin >> beg >> y;
for (int i = 0; i < y; i++)
{
std::cin >> x;
ne[x] = 1;
ban.push_back(x);
}
if (y < sq)
{
int p = 0;
while (p < d[beg].size() && ne[d[beg][p].second])
p++;
if (p == d[beg].size())
std::cout << -1 << '\n';
else
std::cout << d[beg][p].first << '\n';
}
else
{
std::cout << big(beg) << '\n';
}
for (int x : ban)
{
ne[x] = 0;
}
}
return 0;
}
