#pragma GCC optimize("Ofast,unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#define ll int
#define pll pair<int, int>
#define pb push_back
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
const ll N = 1e5 + 100;
const ll inf = 1e9;
const ll mod = 1e9 + 7;
const ll block = 222;
ll n,m,q;
vector<ll>adj[N];
vector<pll>best[N];
ll f[N];
ll vis[N];
bool good[N];
struct ccjv{ll val, u, idx;};
struct cmp{
bool operator()(const ccjv &a, const ccjv &b){
return a.val < b.val;
}
};
void to_thic_cau(){
cin >> n >> m >> q;
for(int i = 1; i <= m;i++){
ll u,v; cin >> u >> v;
adj[v].pb(u);
}
priority_queue<pll> pq;
for (int i = 1; i<=n; i++){
pq.push({0,i});
for (auto u : adj[i]){
for (auto x : best[u]){
ll v = x.F, d = x.S;
pq.push({d+1,v});
}
}
for (;best[i].size()<block && pq.size();pq.pop()){
ll d = pq.top().F, v = pq.top().S;
if (vis[v]!=i){
vis[v]=i;
best[i].pb({v,d});
}
}
for(;pq.size();pq.pop());
}
good[0] = 1;
while(q--){
ll t, sz; cin >> t >> sz;
vector<ll>vec;
for(int i = 1; i <= sz;i++){
ll x; cin >> x;
vec.pb(x);
good[x] = 1; f[x] = -inf;
}
if(t >= block){
for(int i = 1; i <= t;i++) for(auto j : adj[i]) f[i] = max(f[i], f[j] + 1);
cout << (f[t] < 0 ? -1 : f[t]) << '\n';
for(auto x : vec) good[x] = 0, f[x] = 0;
}
else{
ll res = -1;
for(auto x : best[t]){
ll v = x.F, d = x.S;
if(!good[v]) res = max(res, d);
}
for(auto x : vec) good[x] = 0;
cout << res << "\n";
}
}
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
ll tc = 1;
//cin >> tc;
while(tc--) to_thic_cau();
}
