// Created by BJMinhNhut
#include <bits/stdc++.h>
using namespace std;
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define FOR(i, a, b) for(int i = (a), _b = (b); i <= _b; ++i)
#define FORD(i, a, b) for(int i = (a), _b = (b); i >= _b; --i)
#define ALL(a) (a).begin(), (a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define MASK(i) (1ll<<(i))
#define BIT(t, i) (((t)>>(i))&1)
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<ll, ll> pll;
typedef pair<int, int> ii;
/***Common Functions***/
template <class T>
bool minimize(T &a, T b) {
if (a > b) {
a = b;
return true;
}
return false;
}
template <class T>
bool maximize(T &a, T b) {
if (a < b) {
a = b;
return true;
}
return false;
}
template<class T>
void read(T &a) {
a = 0;
char c;
while (!isdigit(c = getchar())) {}
do {
a = a*10 + (c-'0');
} while (isdigit(c = getchar()));
}
template<class T>
void write(T a){
if (a > 9) write(a/10);
putchar(a%10 + '0');
}
/***End of Template***/
int numNodes, numEdges, numQueries;
const int N = 1e5+5;
vi to[N];
const int SQRT = 500;
ii dp[N][SQRT]; //dp[i][j]: j-th longest path to node i
int tmp[N];
bool checked[N];
void Input() {
cin >> numNodes >> numEdges >> numQueries;
FOR(i, 1, numEdges) {
int u, v; cin >> u >> v;
to[u].pb(v);
}
}
void update(int cur, int nxt) {
vector<ii> tmp(0);
tmp.reserve(SQRT);
int i = 0, j = 0;
while (tmp.size() < SQRT) {
if (i == SQRT) tmp.pb(make_pair(dp[cur][j].first >= 0 ? dp[cur][j].first+1 : dp[cur][j].first, dp[cur][j].second)), ++j;
else if (j == SQRT) tmp.pb(dp[nxt][i]), ++i;
else {
ii nxtdp = dp[nxt][i], curdp = mp(dp[cur][j].first >= 0 ? dp[cur][j].first+1 : dp[cur][j].first, dp[cur][j].second);
if (curdp < nxtdp) tmp.pb(nxtdp), ++i;
else if (curdp == nxtdp) tmp.pb(nxtdp), ++i, ++j;
else tmp.pb(curdp), ++j;
}
}
for(int i = 0; i < SQRT; ++i) dp[nxt][i] = tmp[i];
}
void Solve() {
memset(dp, -0x3f, sizeof dp);
FOR(i, 1, numNodes) dp[i][0] = make_pair(0, i);
FOR(i, 1, numNodes) {
for(int j : to[i]) update(i, j);
}
// FOR(i, 0, numNodes-1) {
// cout << dp[3][i].first << ' ' << dp[3][i].second << '\n';
// }
memset(checked, 0, sizeof checked);
while (numQueries--) {
int target; cin >> target;
int absence; cin >> absence;
if (absence < SQRT) {
vi abslist(0);
while (absence--) {
int u; cin >> u;
checked[u] = true;
abslist.pb(u);
}
int best = 0;
while (dp[target][best].second >= 1 && checked[dp[target][best].second]) ++best;
cout << max(-1, dp[target][best].first) << '\n';
for(int u : abslist) checked[u] = false;
} else {
FOR(i, 1, target) tmp[i] = 0;
while (absence--) {
int u; cin >> u;
tmp[u] = -1e9;
}
FOR(i, 1, target) if (tmp[i] >= 0) for(int j : to[i]) maximize(tmp[j], tmp[i] + 1);
cout << max(-1, tmp[target]) << '\n';
}
}
}
int main() {
ios::sync_with_stdio(0); cin.tie(0);
if (fopen("inputf.in", "r")) freopen("inputf.in", "r", stdin);
Input(), Solve();
return 0;
}
