#include <bits/stdc++.h>
#define ll long long
// #define int long long
#define fi first
#define se second
#define pb push_back
#define vi vector <int>
#define pii pair <int, int>
#define FOR(i, a, b) for(int i = a; i <= (int)b; i++)
#define FORD(i, a, b) for(int i = a; i >= (int)b; i--)
#define ALL(A) A.begin(), A.end()
using namespace std;
const int maxn = 2e5 + 5;
int n, m, q;
vector <int> g[maxn];
vector <pair <int, int>> dp[maxn];
int f[maxn];
int vis[maxn];
signed main(void)
{
cin.tie(nullptr) -> sync_with_stdio(false);
#define taskname "kieuoanh"
if(fopen(taskname".inp", "r"))
{
freopen(taskname".inp", "r", stdin);
freopen(taskname".out", "w", stdout);
}
cin >> n >> m >> q;
FOR(i,1,m)
{
int u,v; cin>>u>>v;
g[v].push_back(u);
}
FOR(i,1,n)
{
vector<pair<int,int>> save;
save.push_back({0, i});
for(int &j : g[i])
{
for(auto x : dp[j])
{
save.push_back(make_pair(x.first + 1, x.second));
}
}
sort(ALL(save), greater <pair <int, int>> ());
for(auto x : save)
{
int v = x.se;
if(vis[v] == 0 && dp[i].size() <= 300)
{
dp[i].push_back(x);
vis[v] = 1;
}
}
for(auto x : save) vis[x.se] = 0;
}
memset(f, - 0x3f, sizeof f);
while(q--)
{
int st, k; cin >> st >> k;
vector <int> vers;
FOR(i, 1, k)
{
int x; cin >> x;
vis[x] = 1;
vers.pb(x);
}
if(k <= 300)
{
int ans = -1;
for(auto x : dp[st])
{
if(vis[x.se] == 0) ans = max(ans, x.fi);
}
cout << ans << "\n";
} else
{
FOR(i,1,st) f[i] = -2e9;
FOR(i,1,st)
{
if(vis[i] == 0) f[i] = 0;
for(int &j : g[i]) f[i] = max(f[i], f[j] + 1);
}
cout << (f[st] >=0 ? f[st] : -1) << "\n";
}
for(auto x : vers) vis[x] = 0;
}
return 0;
}
