//by szh
#include<bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pii pair<int,int>
#define pll pair<long long,long long>
#define pb push_back
#define debug(x) cerr<<#x<<"="<<x<<endl
#define pq priority_queue
#define inf 0x3f
#define rep(i,a,b) for (int i=a;i<(b);i++)
#define MP make_pair
#define SZ(x) (int(x.size()))
#define ll long long
#define mod 1000000007
#define ALL(x) x.begin(),x.end()
void inc(int &a,int b) {a=(a+b)%mod;}
void dec(int &a,int b) {a=(a-b+mod)%mod;}
int lowbit(int x) {return x&(-x);}
ll p0w(ll base,ll p) {ll ret=1;while(p>0){if (p%2ll==1ll) ret=ret*base%mod;base=base*base%mod;p/=2ll;}return ret;}
const int maxn = 2e5+10;
int sz = 300;
int n,m,q;
vector <int> edge[maxn];
vector <pii> mx[maxn];
bool bad[maxn];
bool have[maxn];
vector <pii> tmp;
int dp[maxn];
int getdp(int pos) {
if (dp[pos]!=-1) return dp[pos];
dp[pos] = -mod;
if (!bad[pos]) dp[pos] = 0;
for (int v:edge[pos]) dp[pos] = max(dp[pos],getdp(v)+1);
return dp[pos];
}
int main() {
// freopen("input.txt","r",stdin);
std::ios::sync_with_stdio(false);cin.tie(0);
cin>>n>>m>>q;
rep(i,0,m) {
int u,v;cin>>u>>v;
edge[v].pb(u);
}
rep(i,1,n+1) {
mx[i].pb({0,i});
for (int v:edge[i]) {
int cur = 0, cur1 = 0;
while (cur<SZ(mx[i]) and cur1<SZ(mx[v]) and SZ(tmp)<=sz) {
if (mx[i][cur].fi>mx[v][cur1].fi + 1) {
if (!have[mx[i][cur].se]) tmp.pb(mx[i][cur]),have[tmp.back().se]=true;
cur++;
}
else {
if (!have[mx[v][cur1].se]) tmp.pb(MP(mx[v][cur1].fi+1,mx[v][cur1].se)),have[tmp.back().se]=true;
cur1++;
}
}
while (cur<SZ(mx[i]) and SZ(tmp)<=sz) {
if (!have[mx[i][cur].se]) tmp.pb(mx[i][cur]),have[tmp.back().se]=true;
cur++;
}
while (cur1<SZ(mx[v]) and SZ(tmp)<=sz) {
if (!have[mx[v][cur1].se]) tmp.pb(MP(mx[v][cur1].fi+1,mx[v][cur1].se)),have[tmp.back().se]=true;
cur1++;
}
mx[i] = tmp;
while(!tmp.empty()) have[tmp.back().se] = false, tmp.pop_back();
}
}
while (q--) {
vector <int> tmpp;
int pos,e;cin>>pos>>e;
rep(i,0,e) {
int x;cin>>x;
tmpp.pb(x);
bad[x] = true;
}
if (e<sz) {
int cur=0;
while (cur<SZ(mx[pos]) and bad[mx[pos][cur].se]) cur++;
if (cur<SZ(mx[pos])) cout<<mx[pos][cur].fi<<"\n";
else cout<<"-1\n";
}
else {
rep(i,1,pos+1) dp[i] = -1;
int ans = getdp(pos);
if (ans>=0) cout<<getdp(pos)<<"\n";
else cout<<"-1\n";
}
while (!tmpp.empty()) bad[tmpp.back()] = false,tmpp.pop_back();
}
return 0;
}
