#include <bits/stdc++.h>
#define vi vector<int>
#define ve vector
#define ll long long
#define vf vector<float>
#define vll vector<pair<ll,ll>>
#define ii pair<int,int>
#define pll pair<ll,ll>
#define vvi vector<vi>
#define vii vector<ii>
#define gii greater<ii>
#define pb push_back
//#define mp make_pair
#define fi first
#define se second
#define INF 1e9
#define eps 1e-7
#define eps1 1e-2
#define optimise ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define MAX_A 2e5+5
using namespace std;
const int MOD = 998244353;
const int nax = 1e5+5;
const int nax2 = 20;
typedef complex<int> Point;
using cd = complex<double>;
const int batch = 150;
vi prv[nax], dp;
vii fr[nax];
int vis[nax], val[nax], cur[nax], cnt = 0;
int dfs(int u, int q){
int mx = 0;
if(cur[u] == q) mx = -1;
for(auto x : prv[u]){
if(dp[x] == -1) continue;
if(dp[x] != -2) {
mx = max(mx,dp[x]+1);
continue;
}
int a = dfs(x,q);
if(a == -1) continue;
mx = max(mx, a+1);
}
return dp[u] = mx;
}
bool cmp(int x, int y){
return val[x] > val[y];
}
int main()
{
optimise;
int n,m,q;
cin >> n >> m >> q;
for(int i = 0;i < m; i++){
int x,y;
cin >> x >> y;
x--,y--;
prv[y].pb(x);
}
for(int i= 0; i < n; i++){
ve<int> all;
for(auto x : prv[i]){
for(auto y : fr[x]){
if(vis[y.se] != i){
vis[y.se] = i;
all.pb(y.se);
val[y.se] = y.fi+1;
} else val[y.se] = max(val[y.se], y.fi+1);
}
if(vis[x] != i){
vis[x] = i;
all.pb(x);
val[x] = 1;
}
}
all.pb(i);
sort(all.begin(), all.end(), cmp);
for(int j = 0; j < min(batch, (int) all.size()); j++){
fr[i].pb({val[all[j]], all[j]});
}
}
memset(cur, -1,sizeof cur);
while(q--){
int l; cin >> l; l--;
int r; cin >> r;
for(int i = 0; i < r; i++){
int x;
cin >> x;
cur[x-1] = q;
}
if(r < batch){
int res = -1;
for(auto x : fr[l]){
if(cur[x.se] == q) continue;
res = x.fi;
break;
}
cout << res << endl;
} else {
dp.clear();
dp.assign(n,-2);
cout << dfs(l, q) << endl;
}
}
}
