#include<bits/stdc++.h>
#include <cstdio>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;
#define N 100050
#define ff first
#define ss second
#define int long long
#define pb push_back
#define mp make_pair
#define pii pair<int,int>
#define vi vector<int>
#define mii map<int,int>
#define pqb priority_queue<int>
#define pqs priority_queue<int,vi,greater<int> >
#define setbits(x) __builtin_popcountll(x)
#define zrobits(x) __builtin_ctzll(x)
#define mod 1000000007
#define inf 1e18
#define ps(x,y) fixed<<setprecision(y)<<x
#define mk(arr,n,type) type *arr=new type[n];
#define w(x) int x; cin>>x; while(x--)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> pbds;
void c_p_c()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
}
const int B = 150;
bool not_taken[N];
vector<int>gr[N];
vector<int>grr[N];
int dp[N];
vector<pii>dist[N];
int32_t main()
{
c_p_c();
int n, m, q;
cin >> n >> m >> q;
for (int i = 1; i <= m; i++)
{
int a, b;
cin >> a >> b;
gr[a].pb(b);
grr[b].pb(a);
}
///// precomputation
for (int node = 1; node <= n; node++)
{
vector<pii>child_and_dist;
for (auto child : grr[node])
{
for (auto j : dist[child])
{
child_and_dist.pb({j.ff + 1, j.ss});
}
}
child_and_dist.pb({0, node});
int num_taken = 0;
sort(child_and_dist.begin(), child_and_dist.end(), greater<pii>());
map<int, int>rep;
for (int j = 0; j < (int)child_and_dist.size() && num_taken < B; j++)
{
if (rep.find(child_and_dist[j].ss) == rep.end())
{
num_taken++;
dist[node].pb({child_and_dist[j]});
rep[child_and_dist[j].ss] = 1;
}
}
rep.clear();
}
for (int i = 0; i <= n; i++)
not_taken[i] = 0;
while (q--)
{
int p, q;
cin >> p >> q;
vector<int>not_take;
for (int i = 1; i <= q; i++)
{
int r; cin >> r;
not_take.pb(r);
not_taken[r] = 1;
}
///////////////////////////
if (q < B)
{
int ans = -1;
for (auto i : dist[p])
{
if (not_taken[i.second] )
continue;
ans = i.first;
break;
}
cout << ans << '\n';
}
else
{
for (int i = 1; i <= p; i++)
{
dp[i] = 0;
}
for (int i = 1; i <= p; i++)
{
if (not_taken[i] && dp[i] == 0)
continue;
for (auto child : gr[i])
{
dp[child] = max(dp[child], dp[i] + 1);
}
}
cout << dp[p] << '\n';
}
for (auto i : not_take)
not_taken[i] = 0;
}
}
