#include<iostream>
#include<vector>
#include<algorithm>
#include<queue>
#include<set>
#include<queue>
#define pb push_back
using namespace std;
const int N = (int)1e5 + 5;
int n , m, q, u, v, t, y, x, ret = -1, dis[N], mx = 0;
bool bad[N];
vector<int> out[N], in[N];
queue<int> qu;
void bfs(){
qu.push(t); dis[t] = 0;
while(!qu.empty()){
int v = qu.front(); qu.pop();
for(auto u : in[v]){
if(dis[v] + 1 < dis[u]){
dis[u] = dis[v] + 1, qu.push(u);
}
}
}
for(int v = 1; v <= n; v ++){
if(bad[v]) continue;
// cout << v << " " << dis[v] << endl;
if(dis[v] != 1000000000)ret = max(ret, dis[v]);
for(auto u : out[v])if(dis[u] != 1000000000)ret= max(ret, 1 + dis[u]);
}
}
int main(){
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> m >> q;
for(int i = 0; i < m; i ++){
cin >> u >> v;
out[u].pb(v); in[v].pb(u);
}fill(dis, dis + n + 2, 1000000000);
while(q --){
cin >> t >> y;
while(y --)cin >> x, bad[x] = 1;
bfs();
cout << ret << endl;
}exit(0);
}
