#define DEBUG 0
#include <bits/stdc++.h>
using namespace std;
#if DEBUG
// basic debugging macros
int __i__,__j__;
#define printLine(l) for(__i__=0;__i__<l;__i__++){cout<<"-";}cout<<endl
#define printLine2(l,c) for(__i__=0;__i__<l;__i__++){cout<<c;}cout<<endl
#define printVar(n) cout<<#n<<": "<<n<<endl
#define printArr(a,l) cout<<#a<<": ";for(__i__=0;__i__<l;__i__++){cout<<a[__i__]<<" ";}cout<<endl
#define print2dArr(a,r,c) cout<<#a<<":\n";for(__i__=0;__i__<r;__i__++){for(__j__=0;__j__<c;__j__++){cout<<a[__i__][__j__]<<" ";}cout<<endl;}
#define print2dArr2(a,r,c,l) cout<<#a<<":\n";for(__i__=0;__i__<r;__i__++){for(__j__=0;__j__<c;__j__++){cout<<setw(l)<<setfill(' ')<<a[__i__][__j__]<<" ";}cout<<endl;}
// advanced debugging class
// debug 1,2,'A',"test";
class _Debug {
public:
template<typename T>
_Debug& operator,(T val) {
cout << val << endl;
return *this;
}
};
#define debug _Debug(),
#else
#define printLine(l)
#define printLine2(l,c)
#define printVar(n)
#define printArr(a,l)
#define print2dArr(a,r,c)
#define print2dArr2(a,r,c,l)
#define debug
#endif
// define
#define MAX_VAL 999999999
#define MAX_VAL_2 999999999999999999LL
#define EPS 1e-6
#define mp make_pair
#define pb push_back
// typedef
typedef unsigned int UI;
typedef long long int LLI;
typedef unsigned long long int ULLI;
typedef unsigned short int US;
typedef pair<int,int> pii;
typedef pair<LLI,LLI> plli;
typedef vector<int> vi;
typedef vector<LLI> vlli;
typedef vector<pii> vpii;
typedef vector<plli> vplli;
// ---------- END OF TEMPLATE ----------
vi adjList[100000],C;
vpii best[100000];
int del[100000];
int dp[100000];
int main() {
int i,j,k;
int N,M,Q;
int S,E,T,Y;
scanf("%d %d %d",&N,&M,&Q);
for (i = 0; i < M; i++) scanf("%d %d",&S,&E),adjList[E-1].pb(S-1);
for (i = 0; i < N; i++) {
best[i].pb(mp(0,i));
for (j = 0; j < adjList[i].size(); j++) {
int v = adjList[i][j];
for (k = 0; k < best[v].size(); k++) best[i].pb(mp(best[v][k].first+1,best[v][k].second));
}
int c = 0;
sort(best[i].begin(),best[i].end(),greater<pii>());
for (j = 0; j < best[i].size(); j++) {
if (!del[best[i][j].second]) best[i][c++] = best[i][j],del[best[i][j].second] = 1;
}
for (j = 0; j < c; j++) del[best[i][j].second] = 0;
best[i].resize(min(80,c));
}
for (i = 0; i < Q; i++) {
scanf("%d %d",&T,&Y),T--;
C.resize(Y);
for (j = 0; j < Y; j++) scanf("%d",&C[j]),C[j]--,del[C[j]] = 1;
for (j = 0; j < best[T].size(); j++) {
if (!del[best[T][j].second]) break;
}
if (j < best[T].size()) printf("%d\n",best[T][j].first);
else {
for (j = 0; j <= T; j++) {
dp[j] = del[j] ? -1e9:0;
for (k = 0; k < adjList[j].size(); k++) dp[j] = max(dp[j],dp[adjList[j][k]]+1);
}
printf("%d\n",(dp[T] < 0) ? -1:dp[T]);
}
for (j = 0; j < Y; j++) del[C[j]] = 0;
}
return 0;
}
