#include<bits/stdc++.h>
#define st first
#define nd second
#define mp make_pair
#ifndef LOCAL
#define cerr if(0)cerr
#endif
using namespace std;
using ll = long long;
using ld = long double;
using vi = vector<int>;
using pii = pair<int, int>;
const int N = 1e5+1, M = 2e5+1, Bucket = 400;
int n, m, q, t[N], s[N];
int ans[N];
vector<int> g[N], block[N], queries[N];
vector<pii> vec[N];
bool vis[N], blocked[N];
int calc[N];
int brute(int x) {
if(vis[x]==1) {
return calc[x];
}
vis[x] = 1;
calc[x] = 0;
int res = 0;
for(int i: g[x]) {
res = max(res, brute(i)+1);
}
if(res==0 && blocked[x]) {
res = -1;
}
calc[x] = res;
return res;
}
int ptr[N];
int main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin>>n>>m>>q;
for(int i=0; i<m; ++i) {
int a, b; cin>>a>>b;
g[b].push_back(a);
}
for(int i=0; i<q; ++i) {
ans[i] = -1;
cin>>t[i]>>s[i];
block[i].resize(s[i]);
for(int j=0; j<s[i]; ++j) {
cin>>block[i][j];
}
if(s[i]>=Bucket) {
for(int j: block[i]) {
blocked[j] = 1;
}
ans[i] = brute(t[i]);
for(int j=1; j<=n; ++j) {
vis[j] = blocked[j] = 0;
}
}
else {
queries[t[i]].push_back(i);
}
}
for(int i=1; i<=n; ++i) {
for(int iter=0; iter<Bucket; ++iter) {
pii best = mp(0, 0);
for(int j: g[i]) {
while(ptr[j] < (int)vec[j].size() && vis[vec[j][ptr[j]].nd]) {
ptr[j]++;
}
if(ptr[j] < (int)vec[j].size()) {
best = max(best, mp(vec[j][ptr[j]].st+1, vec[j][ptr[j]].nd));
}
}
if(best == mp(0, 0)) {
break;
}
vis[best.nd] = 1;
vec[i].push_back(best);
}
if((int)vec[i].size() < Bucket) {
vec[i].push_back(mp(0, i));
}
for(int j: g[i]) {
ptr[j] = 0;
}
for(auto j: vec[i]) {
vis[j.nd] = 0;
}
for(int j: queries[i]) {
for(int k: block[j]) {
blocked[k] = 1;
}
for(auto k: vec[i]) {
if(!blocked[k.nd]) {
ans[j] = k.st;
break;
}
}
for(int k: block[j]) {
blocked[k] = 0;
}
}
}
for(int i=0; i<q; ++i) {
cout<<ans[i]<<'\n';
}
}
