#include <bits/stdc++.h>
#define f first
#define s second
using namespace std;
vector<int> a[100001], b[100001];
vector<pair<int, int>> luu[100001];
int mx[100001];
int s = 320;
int dp[100001];
vector<bool> tag(100001, false), vst(100001, false);
vector<int> topo;
void dfs(int u){
vst[u] = true;
for (int v:b[u]){
if(!vst[v])dfs(v);
}
topo.push_back(u);
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
int n, m, q;
cin >> n >> m >> q;
for (int i = 1;i<=m;++i){
int u, v;
cin >> u >> v;
a[u].push_back(v);
b[v].push_back(u);
}
for (int u = 1;u<=n;++u){
luu[u].push_back({0, u});
for (int v:b[u]){
for (auto i:luu[v]){
if(mx[i.s]==0){
luu[u].push_back(i);
mx[i.s] = i.f+1;
}else mx[i.s] = max(mx[i.s], i.f+1);
}
}
sort(luu[u].begin(), luu[u].end(), [](pair<int, int> p, pair<int, int> q){
return mx[p.s] > mx[q.s];
});
while(luu[u].size() > s){
auto [d, v] = luu[u].back();
mx[v] = 0;
luu[u].pop_back();
}
for (auto &i:luu[u]){
i.f = mx[i.s];
mx[i.s] = 0;
}
}
while(q--){
int t, y;
cin >> t >> y;
vector<int> tmp;
for (int i = 1;i<=y;++i){
int tt;
cin >> tt;
tag[tt] = true;
tmp.push_back(tt);
}
if(y<s){
int res = -1;
for (auto i:luu[t]){
if(!tag[i.s]){
res= i.f;
break;
}
}
for (int i:tmp){
tag[i] = false;
}
cout << res << '\n';
}else{
int res = -1;
for (int i =1;i<=n;++i){
dp[i] = -1;
vst[i] = false;
}
topo.clear();
dfs(t);
reverse(topo.begin(), topo.end());
dp[t] = 0;
for (int u:topo){
for (int v:b[u]){
dp[v] = max(dp[v], dp[u]+1);
}
}
for (int i = 1;i<=n;++i){
if(!tag[i])res = max(res, dp[i]);
}
for (int i:tmp){
tag[i] = false;
}
cout << res << '\n';
}
}
}
