#include <bits/stdc++.h>
#define fi first
#define sc second
using namespace std;
const int N = 100005;
const int SQ = 330;
vector<vector<int>> g(N), rv(N);
vector<pair<int, int>> dp[N];
int ans = -1;
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n, m, q;
cin >> n >> m >> q;
for(int i = 0;i<m;i++){
int u, v;
cin >> u >> v;
g[u].push_back(v);
rv[v].push_back(u);
}
dp[1].push_back({0, 1});
for(int i = 2;i<=n;i++){
vector<int> ptr(rv[i].size(), 0);
unordered_set<int> s;
for(int c = 0;c<SQ;c++){
pair<int, int> a = {-1, -1};
int idx = -1;
for(int j = 0;j<rv[i].size();j++){
if(ptr[j] < dp[rv[i][j]].size()){
while(ptr[j] < dp[rv[i][j]].size() && s.count(dp[rv[i][j]][ptr[j]].sc)){
++ptr[j];
}
if(ptr[j] < dp[rv[i][j]].size() && dp[rv[i][j]][ptr[j]].fi > a.fi){
a.fi = dp[rv[i][j]][ptr[j]].fi;
a.sc = dp[rv[i][j]][ptr[j]].sc;
idx = j;
}
}
}
if(idx == -1){
break;
}
++ptr[idx];
dp[i].push_back({a.fi + 1, a.sc});
s.insert(a.sc);
}
dp[i].push_back({0, i});
}
bool come[N];
for(int i = 1;i<N;i++){
come[i] = 1;
}
while(q--){
int x, h;
cin >> x >> h;
int a[h];
for(int i = 0;i<h;i++){
cin >> a[i];
come[a[i]] = 0;
}
if(h < SQ){
for(auto p : dp[x]){
if(come[p.sc]){
ans = p.fi;
break;
}
}
}else{
vector<int> mx(N, -1);
mx[x] = 0;
for(int i = x - 1;i>=1;i--){
for(auto u : g[i]){
if(u > x) continue;
mx[i] = max(mx[i], mx[u]);
}
}
for(int i = 1;i<=x;i++){
if(come[i]){
ans = max(ans, mx[i]);
}
}
}
for(int i = 0;i<h;i++){
come[a[i]] = 1;
}
cout << ans << '\n';
ans = -1;
}
}
