#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e5;
const int BLOCK = 320;
int N, M, Q;
vector<int> to[MAXN + 10];
struct dat {
int w, u;
dat(int w_, int u_) : w(w_), u(u_) {}
dat(const dat& d) : w(d.w), u(d.u) {}
// datA before datB if datA.w > datB.w
bool operator<(dat d) const {
if(w == d.w) return u < d.u;
return w > d.w;
}
};
vector<int> from[MAXN + 10];
int qi = 0;
int bad[MAXN + 10];
int dp[MAXN + 10];
int solve1(int V) {
for(int v = 1; v <= V; v++) {
if(bad[v] != qi) dp[v] = 0;
else dp[v] = -1e9;
for(int u : from[v]) {
dp[v] = max(dp[v], 1 + dp[u]);
}
}
if(dp[V] < 0) dp[V] = -1;
return dp[V];
}
vector<dat> best[MAXN + 10];
int done[MAXN + 10], di = 0;
void work(int u) {
vector<dat> cp(best[u].begin(), best[u].end());
for(dat& it : cp) it.w++;
for(int v : to[u]) {
auto mIt = best[v].insert(best[v].end(), cp.begin(), cp.end());
inplace_merge(best[v].begin(), mIt, best[v].end());
vector<dat> cpV; cpV.reserve(BLOCK);
++di;
for(auto it : best[v]) {
if(done[it.u] < di) {
done[it.u] = di;
cpV.push_back(it);
}
if(cpV.size() >= BLOCK) break;
}
best[v].swap(cpV);
}
}
int solve2(int V) {
for(auto& it : best[V]) {
if(bad[it.u] != qi) return it.w;
}
if(bad[V] != qi) return 0;
return -1;
}
int main() {
assert(scanf("%d%d%d", &N, &M, &Q) == 3);
for(int i = 0; i < M; i++) {
int u, v; assert(scanf("%d%d", &u, &v) == 2);
to[u].push_back(v);
from[v].push_back(u);
}
for(int u = 1; u <= N; u++) {
best[u].emplace_back(0, u);
}
for(int u = 1; u <= N; u++) {
work(u);
}
for(qi = 1; qi <= Q; qi++) {
int dest, badc;
assert(scanf("%d%d", &dest, &badc) == 2);
for(int i = 0; i < badc; i++) {
int v; assert(scanf("%d", &v) == 1);
bad[v] = qi;
}
int res = -1;
if(badc >= BLOCK) res = solve1(dest);
else res = solve2(dest);
printf("%d\n", res);
}
}
