#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 1e5 + 5;
const int BASE = 150;
// 保存原始边信息
vector<int> edges[MAX_N];
// 保存颠倒后边信息
vector<int> edges2[MAX_N];
// 保存入度信息
int in2[MAX_N];
// 保存和u距离 最远的BASE个node信息
// first：距离
// second：节点编号
vector<pair<int, int>> maxb[MAX_N];
// 保存到u的最远距离
int dist[MAX_N];
// 0表示可用，1表示被禁止
int tag[MAX_N];
int n, m, q;
void process() {
int start, y;
cin >> start >> y;
// 如果禁用比较多
if (y >= BASE) {
// 初始化距离为-1
memset(dist, -1, sizeof(dist));
memset(tag, 0, sizeof(tag));
// 读取y个禁用点
for (int i = 0; i < y; i++) {
int x;
cin >> x;
tag[x] = 1;
}
// 在颠倒图中进行拓扑排序
queue<int> q;
q.push(start);
dist[start] = 0;
while (!q.empty()) {
int u = q.front();
q.pop();
for (int v : edges[u]) {
in2[v]--;
// 更新dist
dist[v] = max(dist[v], dist[u] + 1);
// 如果入度为0
if (in2[v] == 0) {
q.push(v);
}
}
}
// 统计结果
int ans = -1;
for (int i = 1; i <= n; ++i) {
if (!tag[i]) {
ans = max(ans, dist[i]);
}
}
cout << ans << endl;
}
// 如果禁用比较少
else {
memset(tag, 0, sizeof(tag));
// 读取y个禁用点
for (int i = 0; i < y; i++) {
int x;
cin >> x;
tag[x] = 1;
}
int maxv = -1;
// 遍历和start最远的BASE个
for (auto v : maxb[start]) {
// 如果没有被禁用掉
if (!tag[v.second]) {
maxv = v.first;
break;
}
}
cout << maxv << endl;
}
}
signed main() {
cin >> n >> m >> q;
// 读取边信息
for (int i = 1; i <= m; i++) {
int u, v;
cin >> u >> v;
// 保存原始图
edges[u].push_back(v);
// 保存颠倒以后图
edges2[v].push_back(u);
in2[u]++;
}
for (int i = 1; i <= n; i++) {
if (maxb[i].size() < BASE) {
maxb[i].push_back(make_pair(0, i));
}
for (auto v : edges[i]) {
vector<pair<int, int>> nw;
int it1 = 0, it2 = 0;
while (((it1 != maxb[i].size()) || (it2 != maxb[v].size())) && (nw.size() < BASE)) {
if (it1 == maxb[i].size()) {
if (tag[maxb[v][it2].second]) {
it2++;
continue;
} tag[maxb[v][it2].second] = 1;
nw.push_back(maxb[v][it2]);
it2++;
continue;
}
if (it2 == maxb[v].size()) {
if (tag[maxb[i][it1].second]) {
it1++;
continue;
} tag[maxb[i][it1].second] = 1;
auto t = maxb[i][it1];
t.first++;
nw.push_back(t);
it1++;
continue;
}
if (maxb[i][it1].first + 1 > maxb[v][it2].first) {
if (tag[maxb[i][it1].second]) {
it1++;
continue;
} tag[maxb[i][it1].second] = 1;
auto t = maxb[i][it1];
t.first++;
nw.push_back(t);
it1++;
continue;
}
else {
if (tag[maxb[v][it2].second]) {
it2++;
continue;
} tag[maxb[v][it2].second] = 1;
nw.push_back(maxb[v][it2]);
it2++;
continue;
}
}
swap(nw, maxb[v]);
nw.clear();
for (auto u : maxb[v]) tag[u.second] = 0;
}
}
for (int i = 0; i < q; ++i) {
process();
}
return 0;
}
