#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
typedef vector<pair<int,int>> vii;
const int maxn = 1e5 + 20;
const int sq = 320;
vector<int> in[maxn];
vii path[maxn];
int dp[maxn];
bool is[maxn];
bool cmp(pair<int , int> a , pair<int , int> b)
{
return a > b;
}
void merge(vii &a , vii &b)
{
vii c(a.size() + b.size());
merge(a.begin() , a.end() , b.begin() , b.end() , c.begin() , cmp);
a = c;
while(a.size() > sq)
a.pop_back();
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int n , m , q;
cin >> n >> m >> q;
for(int i = 0; i < m; i++)
{
int a , b;
cin >> a >> b;
a-- , b--;
in[b].pb(a);
}
for(int v = 0; v < n; v++)
{
path[v].pb({-1 , v});
for(auto u : in[v])
merge(path[v] , path[u]);
for(auto &x : path[v])
x.first++;
}
while(q--)
{
int v , sz;
cin >> v >> sz;
v--;
vector<int> tmp(sz);
for(auto &x : tmp)
cin >> x , x--;
for(auto x : tmp)
is[x] = 1;
if(sz > sq)
{
for(int i = 0; i <= v; i++)
{
dp[i] = -1e9;
if(!is[i])
dp[i] = 0;
for(auto u : in[i])
dp[i] = max(dp[i] , dp[u] + 1);
}
dp[v] = max(dp[v] , -1);
cout << dp[v] << endl;
}
else
{
bool f = 0;
for(auto x : path[v])
if(!is[x.second])
{
cout << x.first << endl;
f = 1;
break;
}
if(!f)
cout << -1 << endl;
}
for(auto x : tmp)
is[x] = 0;
}
}
