#include<bits/stdc++.h>
using namespace std;
#define N 1000000
#define ff first
#define ss second
#define int long long
#define pb push_back
#define pii pair<int,int>
void c_p_c()
{
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
}
const int B = 200;
int not_taken[N];
vector<int>gr[N];
vector<int>grr[N];
int dp[N];
set<pii, greater<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 i = 1; i <= n; i++)
{
int node = i;
for (auto child : grr[node])
{
for (auto j : dist[child])
{
dist[node].insert({j.ff + 1, j.ss});
}
}
dist[node].insert({0, node});
while (dist[node].size() >= B)
dist[node].erase(dist[node].end());
}
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 - 1; 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;
}
}
