#include <bits/stdc++.h>
using namespace std;
// #define int long long
#define sp << ' ' <<
#define nl << '\n'
const int INF = 1e9, SQRT = 200, MAXN = 1e5;
const array<int, 2> DEF = {-INF, -1};
signed main(){
cin.tie(0)->sync_with_stdio(0);
int n, m, q, x, y; cin >> n >> m >> q;
vector<int> g[n];
while(m--){
cin >> x >> y;
g[x-1].push_back(y-1);
}
vector<array<int, 2>> dp[n];
for(int u=0; u<n; ++u) dp[u].push_back({0, u});
bool filled[n]; fill(filled, filled+n, false);
for(int u=0; u<n; ++u){
for(int v : g[u]){
vector<array<int, 2>> curr;
array<int, 2> k;
int i = 0, j = 0, iLim = dp[u].size(), jLim = dp[v].size();
while((int)curr.size() <= SQRT and (i < iLim or j < jLim)){
if(i >= iLim){
k = dp[v][j++];
}else if(j >= jLim){
k = dp[u][i++];
++k[0];
}else if(dp[u][i][0] + 1 >= dp[v][j][0]){
k = dp[u][i++];
++k[0];
}else{
k = dp[v][j++];
}
filled[k[1]] = true;
while(i < iLim and filled[dp[u][i][1]]) ++i;
while(j < jLim and filled[dp[v][j][1]]) ++j;
curr.push_back(k);
}
swap(dp[v], curr);
for(auto &i : dp[v]) filled[i[1]] = false;
}
}
bool bad[n]; fill(bad, bad+n, false);
while(q--){
cin >> x >> y; --x;
int c[y]; for(int &i : c) cin >> i, --i, bad[i] = true;
int res = -1;
if(y < SQRT){
for(auto &i : dp[x]){
if(!bad[i[1]]){
res = max(i[0], res);
break;
}
}
}else{
int longest[n];
for(int u=n-1; u>=0; --u){
longest[u] = -INF;
if(u == x) longest[u] = 0;
if(u > x) continue;
for(int v : g[u]){
longest[u] = max(longest[u], longest[v] + 1);
}
if(!bad[u]) res = max(res, longest[u]);
}
}
cout << res nl;
for(int i : c) bad[i] = false;
}
}
