#include <bits/stdc++.h>
#define DEBUG 0
using namespace std;
const int N = 1e5 + 10;
const int M = 30;
const int INF = 1e9 + 7;
vector <int> rev[N];
pair <int, int> node[N][M];
int sz[N];
stack <int> tmp, tmp2;
bool notuse[N];
int dp[N];
int solve(int u) {
if(dp[u] != -1) {
return dp[u];
}
dp[u] = -INF;
for(auto v : rev[u]) {
int x = solve(v);
if(x != -INF) {
dp[u] = max(dp[u], solve(v) + 1);
}
}
if(notuse[u] == false) {
dp[u] = max(dp[u], 0);
}
return dp[u];
}
int main() {
cin.tie(0)->sync_with_stdio(0);
int n, m, q;
cin >> n >> m >> q;
while(m--) {
int s, e;
cin >> s >> e;
rev[e].push_back(s);
}
for(int i = 1; i <= n; i++) {
sz[i] = 1;
for(int j = 1; j <= M; j++) {
node[i][j] = make_pair(-INF, -1);
}
}
for(int u = 1; u <= n; u++) {
for(auto v : rev[u]) {
tmp.push(v);
}
for(int i = 1; i <= M; i++) {
pair <int, int> best = make_pair(-INF, -1);
int idx = -1;
for(auto v : rev[u]) {
while(notuse[node[v][sz[v]].second] == true) {
sz[v]++;
}
if(best.first < node[v][sz[v]].first) {
best = node[v][sz[v]];
idx = v;
}
}
if(best.first == -INF) {
node[u][i] = make_pair(0, u);
break;
}
node[u][i] = make_pair(best.first + 1, best.second);
tmp2.push(best.second);
notuse[best.second] = true;
sz[idx]++;
}
while(!tmp.empty()) {
sz[tmp.top()] = 1;
tmp.pop();
}
while(!tmp2.empty()) {
notuse[tmp2.top()] = false;
tmp2.pop();
}
}
if(DEBUG) {
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= M; j++) {
if(node[i][j].first == -INF) {
break;
}
cout << i << " : " << node[i][j].first << " " << node[i][j].second << endl;
}
cout << endl;
}
}
while(q--) {
int t, y;
cin >> t >> y;
while(y--) {
int c;
cin >> c;
notuse[c] = true;
tmp.push(c);
}
int ans = -INF;
if(y < M) {
for(int i = 1; i <= M; i++) {
if(notuse[node[t][i].second] == false and node[t][i].first != -INF) {
ans = node[t][i].first;
break;
}
}
}
else {
for(int i = 1; i <= t; i++) {
dp[i] = -1;
}
ans = solve(t);
}
if(ans == -INF) {
ans = -1;
}
cout << ans << '\n';
while(!tmp.empty()) {
notuse[tmp.top()] = false;
tmp.pop();
}
}
return 0;
}
