#include <bits/stdc++.h>
#define fi first
#define se second
using namespace std;
using pii = pair<int, int>;
const int MX = 100005;
int n, m, q, B;
int f[MX];
bitset<MX> vist = 0;
vector<int> G[MX];
vector<pii> T[MX];
int32_t main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> n >> m >> q;
B = sqrt(n);
for(int i=1; i<=m; i++){
int u, v;
cin >> u >> v;
G[u].push_back(v);
}
vist = 0;
for(int i=1; i<=n; i++) T[i].push_back({0, i});
for(int u=1; u<=n; u++){
for(int v: G[u]){
if(T[v].size() == 0) T[v] = T[u];
else{
vector<pii> vt;
for(int i=0, j=0; vt.size() <= B && (i < (int)T[u].size() || j < (int)T[v].size());){
if(i < (int)T[u].size() && j < T[v].size()){
pii x = T[u][i]; x.fi++;
pii y = T[v][j];
if(vist[x.se]) { i++; continue; }
if(vist[y.se]) { j++; continue; }
if(x > y){
vist[x.se] = 1;
vt.push_back(x);
i++;
}
else{
vist[y.se] = 1;
vt.push_back(y);
j++;
}
}
else if(i < (int)T[u].size()){
pii x = T[u][i]; x.fi++;
if(vist[x.se]) { i++; continue; }
vist[x.se] = 1;
vt.push_back(x);
i++;
}
else if(j < (int)T[v].size()){
pii y = T[v][j];
if(vist[y.se]) { j++; continue; }
vist[y.se] = 1;
vt.push_back(y);
j++;
}
else break;
}
T[v] = vt;
for(pii x: vt) vist[x.se] = 0;
}
}
}
for(int i=1; i<=q; i++){
int S, k;
cin >> S >> k;
vector<int> vt(k);
for(int &x: vt) cin >> x;
if(vt.size() > B){
vist = 0;
for(int &x: vt) vist[x] = 1;
memset(f, -0x3f, sizeof f);
for(int u=1; u<=n; u++){
if(!vist[u]) f[u] = max(f[u], 0);
for(int v: G[u]) f[v] = max(f[v], f[u] + 1);
}
if(f[S] < 0) cout << -1 << '\n';
else cout << f[S] << '\n';
for(int &x: vt) vist[x] = 0;
}
else{
for(int x: vt) vist[x] = 1;
int ans = -1;
for(pii p: T[S]) if(!vist[p.se]){
ans = p.fi;
break;
}
for(int x: vt) vist[x] = 0;
cout << ans << '\n';
}
}
return 0;
}
