#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pp;
#define rep(i,l,r) for(int i = (l); i < r; i++)
#define per(i,r,l) for(int i = (r); i >= l; i--)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()
#define pb push_back
#define ff first
#define ss second
const ll mod = 1e9 + 7, maxn = 2e5 + 5, maxlg = 21, inf = 1e9 + 5;
int sq = 100;
vector<int> adj[maxn];
vector<pp> best[maxn];
bool is[maxn];
int main(){
cin.tie(0) -> sync_with_stdio(0);
int n, m, q; cin >> n >> m >> q;
rep(i,0,m){
int u, v; cin >> u >> v;
u--, v--;
adj[v].pb(u);
}
rep(i,0,n){
vector<pp> a;
a.pb(pp(-1, i));
for(int r: adj[i]){
for(pp c: best[r]){
a.pb(c);
}
}
sort(all(a));
reverse(all(a));
for(pp c: a){
if(!is[c.ss]){
is[c.ss] = true;
c.ff++;
best[i].pb(c);
}
if(sz(best[i]) == sq) break;
}
for(pp c: best[i]) is[c.ss] = false;
}
while(q--){
int t, c; cin >> t >> c;
vector<int> city;
rep(i,0,c){
int r; cin >> r; r--;
city.pb(r);
is[r] = true;
}
if(c < sq){
for(auto p: best[t - 1]){
if(!is[p.ss]){
cout << p.ff << '\n';
goto hell;
}
}
cout << -1 << '\n';
hell:;
}else{
vector<int> dp(t, -inf);
dp[t-1] = 0;
per(i,t-1,0){
for(int p: adj[i]){
dp[p] = max(dp[i] + 1, dp[p]);
}
}
int mx = -1;
rep(i,0,t){
if(!is[i]) mx = max(mx, dp[i]);
}
cout << mx << '\n';
}
for(int r: city) is[r] = false;
}
return 0;
}
