#include "bits/stdc++.h"
using namespace std;
#define sz(v) (int)v.size()
const int MAX = 1e5 + 5;
const int SQRT = 350;
int n, m, q, dp[MAX], all_dp[MAX];
vector<int> adj[MAX], rev[MAX];
bool bad[MAX], vis[MAX];
vector<int> bestNodes[MAX]; //only take B nodes
vector<int> S[MAX], tmpS;
bool better(int u, int v){
return dp[u] > dp[v];
}
void insert(vector<int>& A, vector<int>& B){ //define A is larger set
vector<int>().swap(tmpS);
int i = 0, j = 0;
while(i < sz(A) || j < sz(B)){
if(sz(tmpS) == SQRT) break;
if(i == sz(A)) tmpS.push_back(B[j++]);
else if(j == sz(B)) tmpS.push_back(A[i++]);
else if(better(A[i], B[j])) tmpS.push_back(A[i++]);
else tmpS.push_back(B[j++]);
}
swap(tmpS, A);
}
int dfsDP(int u){
if(vis[u]) return dp[u];
vis[u] = true;
for(int v : adj[u]){
dp[u] = max(dp[u], dfsDP(v) + 1);
}
return dp[u];
}
queue<int> qu;
void bfsAdj(int s){
vis[s] = true;
qu.push(s);
while(!qu.empty()){
int u = qu.front(); qu.pop();
bestNodes[u] = S[u];
for(int v : adj[u]){
insert(S[v], S[u]);
if(!vis[v]){
insert(S[v], S[u]);
vis[v] = true;
qu.push(v);
}
}
}
}
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> n >> m >> q;
for(int i = 0; i < m; ++i){
int u, v;
cin >> u >> v;
adj[u].push_back(v);
rev[v].push_back(u);
}
for(int i = n; i >= 1; --i){
if(!vis[i]){
dfsDP(i);
}
}
for(int i = 1; i <= n; ++i){ S[i].push_back(i); }
fill(vis + 1, vis + 1 + n, false);
for(int i = 1; i <= n; ++i){
if(!vis[i]){
bfsAdj(i);
}
}
while(q--){
int t, y;
cin >> t >> y;
vector<int> nodes(y);
for(int i = 0; i < y; ++i) cin >> nodes[i];
for(int u : nodes) bad[u] = true;
if(y > SQRT){
fill(dp + 1, dp + 1 + n, -1e9);
dp[t] = 0;
for(int i = t; i > 0; --i){
for(int j : rev[i]){
dp[j] = max(dp[j], dp[i] + 1);
}
}
int ans = -1;
for(int i = t; i > 0; --i){
if(!bad[i]) ans = max(ans, dp[i]);
}
cout << ans << '\n';
} else{
int ans = -1;
for(int i = 0; i < sz(bestNodes[t]); ++i){
if(!bad[bestNodes[t][i]]){
ans = dp[bestNodes[t][i]];
break;
}
}
if(ans == -1){
cout << ans << '\n';
} else{
ans -= dp[t];
cout << ans << '\n';
}
}
for(int u : nodes) bad[u] = false;
}
return 0;
}
