// In the name of Allah
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define endl '\n'
#define sep ' '
#define all(x) (x).begin(),(x).end()
#define len(x) ((ll) (x).size())
#define pb push_back
#define Mp make_pair
#define F first
#define S second
int n, m, q;
const int maxn = 2e5 + 4;
const int sq = 100, oo = 1e9;
vector<int> adj[maxn], adjr[maxn];
int ans[maxn], res[maxn], val[maxn]; vector<int> A[maxn], vc;
vector<pii> dp[maxn]; bool M[maxn];
void solve(int R) {
fill(res, res + R, 0);
for (int v = 0; v < R; v++) {
for (int u : adjr[v]) {
res[v] = max(res[v], res[u] + 1);
}
if (M[v] && res[v] == 0) res[v] = -oo;
}
}
bool cmp(pii a, pii b) {
if (a.S != b.S) return a.S > b.S;
else return a.F > b.F;
}
int main() {
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> m >> q;
for (int i = 0; i < m; i++) {
int u, v;
cin >> u >> v; u--; v--;
adj[u].pb(v); adjr[v].pb(u);
}
fill(val, val + n, -1);
for (int v = 0; v < n; v++) {
vc.clear();
vc.pb(v);
val[v] = 0;
for (int u : adjr[v]) {
for (auto f : dp[u]) {
vc.pb(f.S);
val[f.S] = max(val[f.S], f.F + 1);
}
}
sort(all(vc)); vc.resize(unique(all(vc)) - vc.begin());
for (int u : vc) {
dp[v].pb(Mp(val[u], u));
val[u] = -1;
}
sort(all(dp[v]), greater<pii>()); dp[v].resize(min(sq + 10ll, len(dp[v])));
}
for (int i = 0; i < q; i++) {
int v, T;
cin >> v >> T; v--;
int t = 0;
for (int j = 0; j < T; j++) {
int u;
cin >> u; u--;
if (u <= v) {
A[i].pb(u);
M[u] = 1; t++;
}
}
if (t == v + 1) {
ans[i] = -1;
}
else if (T < sq) {
for (auto f : dp[v]) {
int u = f.S, val = f.F;
if (!M[u]) {
ans[i] = val;
break;
}
}
}
else {
solve(v + 1);
ans[i] = res[v];
}
for (int u : A[i]) M[u] = 0;
}
for (int i = 0; i < q; i++) cout << ans[i] << endl;
return 0;
}
