#include <bits/stdc++.h>
using namespace std;
using PII = pair<int,int>;
#define all(a) begin(a), end(a)
constexpr int blockLen = 100;
int main() {
cin.tie(0) -> sync_with_stdio(0);
int n,m,q; cin >> n >> m >> q;
vector<vector<int>> canals(n + 1);
while (m--) {
int s,e; cin >> s >> e;
canals[e].push_back(s);
}
vector<set<PII>> blocks(n + 1);
for (int i = 1; i <= n; i++) {
for (int e: canals[i]) {
vector<bool> used(n + 1);
auto it1 = begin(blocks[i]), it2 = begin(blocks[e]);
while (it2 != end(blocks[e])) {
while (it1 != end(blocks[i]) && used[it1 -> second]) {
++it1;
blocks[i].erase(prev(it1));
}
while (it2 != end(blocks[e]) && used[it2 -> second]) {
++it2;
}
if (it1 == end(blocks[i]) && it2 == end(blocks[e])) {
break;
}
if (it1 == end(blocks[i]) || (it2 != end(blocks[i])
&& it2 -> first <= it1 -> first)) {
used[it2 -> second] = true;
blocks[i].insert({it2 -> first - 1, it2 -> second});
if (blocks[i].size() > blockLen) {
blocks[i].erase(prev(end(blocks[i])));
}
it2++;
} else {
used[it1 -> second] = true;
it1++;
}
}
}
if (blocks[i].size() < blockLen) {
blocks[i].insert({0, i});
}
}
while (q--) {
int t,y; cin >> t >> y;
vector<bool> busy(n + 1);
for (int i = 0; i < y; i++) {
int a; cin >> a;
busy[a] = 1;
}
if (y >= blockLen) {
vector<int> dp(t+1, -1);
for (int i = 1; i <= t; i++) {
if (!busy[i]) {
dp[i] = max(dp[i], 0);
}
for (int e: canals[i]) {
if (dp[e] != -1) {
dp[i] = max(dp[i], dp[e] + 1);
}
}
}
cout << dp[t] << '\n';
}
else {
bool found = false;
for (PII p: blocks[t]) {
if (!busy[p.second]) {
found = true;
cout << (-1 * p.first) << '\n';
break;
}
}
if (!found) cout << "-1\n";
}
}
}
