#include<bits/stdc++.h>
#define ii pair<int,int>
using namespace std;
const int maxn = 2e5 + 5, bl = 100;
int n, m, q;
int dp[maxn], mark[maxn];
vector<int> adj[maxn], radj[maxn];
vector<ii> path[maxn];
void precompute()
{
for (int i = 1; i <= n; i++)
{
priority_queue<ii, vector<ii>, greater<ii>> pq;
pq.emplace(0, i);
for (int j : adj[i])
{
for (auto [u, v] : path[j])
pq.emplace(u + 1, v);
}
while (pq.size() > bl)
pq.pop();
while (pq.size())
path[i].emplace_back(pq.top()),
pq.pop();
reverse(path[i].begin(), path[i].end());
}
}
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
// freopen("test.inp", "r", stdin);
// freopen("test.out", "w", stdout);
cin >> n >> m >> q;
for (int i = 1, u, v; i <= m; i++)
cin >> u >> v,
adj[v].emplace_back(u),
radj[u].emplace_back(v);
precompute();
while (q--)
{
int T, k, x, ans = -1;
cin >> T >> k;
vector<int> qr;
while (k--)
cin >> x, qr.emplace_back(x), mark[x] = 1;
if (qr.size() >= bl)
{
memset(dp, -0x3f, sizeof dp);
int oo = dp[0];
dp[T] = 0;
for (int i = n; i >= 1; i--)
{
for (int j : radj[i]) if (dp[j] != oo)
dp[i] = max(dp[i], dp[j] + 1);
if (dp[i] != oo && !mark[i])
ans = max(ans, dp[i]);
}
} else
{
for (auto [u, v] : path[T])
if (!mark[v])
{
ans = u;
break;
}
}
cout << ans << "\n";
for (int i : qr) mark[i] = 0;
}
}
