/*****from dust I have come, dust I will be*****/
#include <algorithm>
#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
const int MOD = 1000000007;
using namespace std;
#define int long long
#define forn(i,n) for(int i=0;i<n;i++)
int dx[8] = { 1, 0, -1, 0, -1, 1, -1, 1 };
int dy[8] = { 0, 1, 0, -1, -1, 1, 1, -1 };
int ceil_div(int a, int b) {return a % b == 0 ? a / b : a / b + 1;}
int add(int x, int y) { return (x%MOD + y%MOD)%MOD; }
int sub(int x, int y) { return (x%MOD - y%MOD + MOD)%MOD; }
int mul(int x, int y) { return (x%MOD * y%MOD)%MOD; }
//const int MOD = 998244353;
typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> pbds; // find_by_order, order_of_key
/*
int k = A.order_of_key(p[i].second);
A.erase(A.find_by_order(k));
erase element from pbds multiset
*/
int dfs(int u, vector<vector<int>>& g, vector<bool>& blocked, vector<int>& dp) {
if (dp[u] != -2) return dp[u]; // already computed
int best = 0; // path of length 0 (just this node)
for (int v : g[u]) {
int res = dfs(v, g, blocked, dp);
if (res != -1) best = max(best, res + 1);
}
if (best == 0 && blocked[u]) return dp[u] = -1;
return dp[u] = best;
}
int alg1(vector<vector<int>>& g, vector<bool>& blocked, int target) {
vector<int> dp(g.size(), -2); // -2 = unvisited
return dfs(target, g, blocked, dp);
}
int alg2(vector<vector<int>>&g, vector<bool>&c, int target){
vector<int>res(target + 1, -1);
for (int i=0;i<=target;i++){
res[i] = (c[i] ? -1 : 0);
for (auto t : g[i]){
if (res[t] == -1) continue;
res[i] = max(res[i], res[t] + 1);
}
if (res[i] == 0 && c[i]) res[i] = -1;
}
return res[target];
}
void solve() {
int n,m,q; cin >> n >> m >> q;
vector<vector<int>>g(n), f(n);
for (int i=0;i<m;i++){
int a,b; cin >> a>> b;
a--; b--;
g[b].push_back(a);
f[a].push_back(b);
}
int sq = sqrtl(n);
vector<bool>vis(n, false);
for (int i=0;i<q;i++){
int target, y; cin >> target>> y;
target--;
vector<int>c(y);
for (int i=0;i<y;i++){
cin >> c[i];
c[i]--;
vis[c[i]] = true;
}
int ans;
if (y > sq) ans = alg2(g, vis, target);
else ans = alg1(g, vis, target);
cout << ans<<'\n';
for (int i=0;i<y;i++){
vis[c[i]] = false;
}
}
}
int32_t main(){
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
// #ifndef ONLINE_JUDGE
// freopen("input.txt", "r", stdin);
// freopen("output.txt", "w", stdout);
// #endif
int t = 1;// cin >>t;
for (int i=1;i<=t;i++){
solve();
}
return 0;
}
