#include <bits/stdc++.h>
using namespace std; using ii = pair<int,int>; using ll = long long;
#define rep(i,a,b) for (auto i = (a); i <= (b); ++i)
#define all(x) (x).begin(), (x).end()
#define size(x) int((x).size())
#define Mup(x,y) x = max(x,y)
#define mup(x,y) x = min(x,y)
const int N = 1e5+3, B = 100;
int n, m, q;
vector<int> rdj[N];
int dp[N], c[N];
bool come[N];
vector<ii> distances[N];
#define D first
#define F second
void precalc() {
bool used[N] {0,};
rep(i,1,n) {
for (int j : rdj[i]) {
auto &x = distances[i], &y = distances[j];
vector<ii> tmp; // tmp <- x + y
int a = 0, b = 0;
while (a < size(x) or b < size(y)) {
if (a >= size(x) or (b < size(y) and y[b].D+1 >= x[a].D)) {
if (!used[y[b].F]) tmp.emplace_back(y[b].D+1,y[b].F);
used[y[b].F] = true;
b++;
}
else if (b >= size(y) or (a < size(x) and x[a].D > y[b].D+1)) {
if (!used[x[a].F]) tmp.emplace_back(x[a].D,x[a].F);
used[x[a].F] = true;
a++;
}
if (size(tmp) == B) break;
}
for (ii t : tmp) used[t.F] = false; // used 복구
swap(distances[i],tmp); // distances[i] <- tmp
}
if (size(distances[i]) < B) distances[i].emplace_back(0,i);
}
}
int main() {
scanf("%d%d%d",&n,&m,&q);
rep(i,1,m) {
int s, e; scanf("%d%d",&s,&e);
rdj[e].push_back(s);
}
precalc();
fill(come+1,come+n+1,true);
rep(_,1,q) {
int t, y; scanf("%d%d",&t,&y);
rep(i,1,y) scanf("%d",c+i), come[c[i]] = false;
if (y >= B) {
rep(i,1,t) {
dp[i] = -1e9;
if (come[i]) Mup(dp[i],0);
for (const int &j : rdj[i]) {
Mup(dp[i],dp[j]+1);
}
}
printf("%d\n",max(dp[t],-1));
} else {
int answer = -1e9;
for (const auto &[dist,from] : distances[t]) {
if (come[from]) {
answer = dist;
break;
}
}
printf("%d\n",max(answer,-1));
}
rep(i,1,y) come[c[i]] = true;
}
}
