#include<iostream>
#include<vector>
#include<cstring>
#define all(v) (v).begin(), (v).end()
#define sz(v) (int)(v).size()
#define fi first
#define se second
using namespace std;
const int NMAX = (int)1e5 + 10;
const int INF = (int)1e9 + 7;
const int B = 300;
int N, M, Q;
vector<int> adj[NMAX], radj[NMAX];
vector<pair<int, int>> good[NMAX];
bool used[NMAX];
bool ohno[NMAX];
int dp[NMAX];
int main(void) {
ios_base::sync_with_stdio(0); cout.tie(0); cout.tie(0);
// freopen("a.in", "r", stdin); freopen("a.out", "w", stdout);
cin >> N >> M >> Q;
for(int i = 1; i <= M; i++) {
int u, v; cin >> u >> v;
adj[u].push_back(v);
radj[v].push_back(u);
}
memset(used, false, sizeof used);
for(int i = 1; i <= N; i++) {
for(int j = 0; j < sz(radj[i]); j++) {
vector<pair<int, int>> res;
int u = radj[i][j];
int a = 0, b = 0;
while(sz(res) < B && (a < sz(good[i]) || b < sz(good[u]))) {
if(b == sz(good[u]) || (a < sz(good[i]) && good[i][a].se >= good[u][b].se + 1)) {
res.push_back(good[i][a]);
used[good[i][a].fi] = true;
a++;
}
else {
res.push_back(make_pair(good[u][b].fi, good[u][b].se + 1));
used[good[u][b].fi] = true;
b++;
}
while(a < sz(good[i]) && used[good[i][a].fi]) a++;
while(b < sz(good[u]) && used[good[u][b].fi]) b++;
}
for(int k = 0; k < sz(res); k++) {
used[res[k].fi] = false;
}
swap(good[i], res);
}
good[i].push_back(make_pair(i, 0));
// cout << "i : " << i << ", size: " << sz(good[i]) << '\n';
// for(int j = 0; j < sz(good[i]); j++) {
// cout << good[i][j].fi << ' ' << good[i][j].se << '\n';
// if(j == sz(good[i]) - 1) cout << '\n';
// }
}
memset(ohno, false, sizeof ohno);
while(Q--) {
int v, y; cin >> v >> y;
vector<int> c(y);
for(int &val : c) {
cin >> val;
ohno[val] = true;
}
if(y < B) {
int ans = -1;
for(int i = 0; i < sz(good[v]); i++) if(ohno[good[v][i].fi] == false) {
ans = good[v][i].se;
break;
}
cout << ans << '\n';
}
else {
for(int i = 1; i <= v; i++) dp[i] = (ohno[i] ? -1 : 0);
for(int i = 1; i <= v; i++) {
if(dp[i] < 0 ) continue;
for(int j = 0; j < sz(adj[i]); j++) {
int u = adj[i][j];
dp[u] = max(dp[u], dp[i] + 1);
}
}
cout << dp[v] << '\n';
}
for(int &val : c) {
ohno[val] = false;
}
}
}
