#include<bits/stdc++.h>
using namespace std;
typedef int ll;
typedef vector<ll> vll;
typedef pair<ll,ll> pll;
typedef long double ld;
#define RETD(x) cout << fixed << setprecision(15) << x;
#define X first
#define Y second
#define PB push_back
#define For(i,a,b) for(ll i=a;i<b;i++)
#define SZ(x) ((ll)(x.size()))
#define smax(a,b) a=max(a,b)
#define ER(x) cout << #x << ' ' << x << '\n'
#define MKP make_pair
#define smin(a,b) a=min(a,b);
const ll M=1e5+5,inf=1e9,SM=100;
typedef complex<ld> point;
pair<ld,point> p[M];
ll n,m,q;
vector<pll> dp[M];
ll res[M];
vector<ll> g[M];
void merg(ll x,ll y){
for(pll f:dp[x]){
res[f.Y]=f.X;
}
for(pll f:dp[y]){
smin(res[f.Y],f.X-1);
}
For(i,0,SZ(dp[x])){
dp[x][i].X=res[dp[x][i].Y];
res[dp[x][i].Y]=0;
}
For(i,0,SZ(dp[y])){
if (res[dp[y][i].Y]){
dp[x].PB({dp[y][i].X-1,dp[y][i].Y});
res[dp[y][i].Y]=0;
}
}
sort(dp[x].begin(),dp[x].end());
while (SZ(dp[x])>SM) dp[x].pop_back();
}
vll qud;
ll mark[M];
ll tmp[M];
int main()
{
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n >> m >> q;
For(i,0,m){
ll u,v;
cin >> u >> v;
u--;v--;
g[v].PB(u);
}
For(x,0,n){
//ER(x);
for (ll y:g[x]){
//ER(y);
merg(x,y);
}
if (SZ(dp[x])<SM){
dp[x].PB({0,x});
}
}
while (q--){
//ER(q);
ll v,c;
cin >> v >> c;
v--;
For(i,0,c){
ll x;
cin >> x;
x--;
qud.PB(x);
mark[x]=1;
}
if (c<SM){
bool ah=0;
for (pll x:dp[v]){
//ER(x.Y << ' ' << mark[x.Y]);
if (!mark[x.Y]){
cout << -x.X << '\n';
ah=1;
break;
}
}
if (!ah) cout << "-1\n";
}else{
For(i,0,v+1){
tmp[i]=0;
if (mark[i]){
tmp[i]=-1;
}
for (ll y:g[i]){
if (tmp[y]==-1) continue;
smax(tmp[i],tmp[y]+1);
}
}
cout << tmp[v] << '\n';
}
for (ll f:qud){
mark[f]=0;
}
qud.clear();
}
}
