#include <bits/stdc++.h>
using namespace std;
#define X first
#define Y second
#define mp make_pair
#define pb push_back
#define Debug(...) fprintf(stderr, __VA_ARGS__)
typedef long long LL;
typedef long double LD;
typedef unsigned int uint;
typedef pair <int, int> pii;
typedef unsigned long long uLL;
template <typename T> inline void Read(T &x) {
char c = getchar();
bool f = false;
for (x = 0; !isdigit(c); c = getchar()) {
if (c == '-') {
f = true;
}
}
for (; isdigit(c); c = getchar()) {
x = x * 10 + c - '0';
}
if (f) {
x = -x;
}
}
template <typename T> inline bool CheckMax(T &a, const T &b) {
return a < b ? a = b, true : false;
}
template <typename T> inline bool CheckMin(T &a, const T &b) {
return a > b ? a = b, true : false;
}
const int N = 100005;
const int M = 325;
int n, m, q, tim, top, f[N], seq[N], siz[N], vis[N];
vector <int> adj[N], rev[N];
pii dis[N][M];
bool ban[N];
inline void Merge(int x, int y) {
static pii tmp[M << 1];
++tim, top = 0;
for (int i = 1, j = 1; i <= siz[x] || j <= siz[y]; ) {
if (i <= siz[x] && (j > siz[y] || dis[x][i].X >= dis[y][j].X + 1)) {
if (vis[dis[x][i].Y] != tim) {
vis[dis[x][i].Y] = tim, tmp[++top] = dis[x][i];
}
++i;
} else {
if (vis[dis[y][j].Y] != tim) {
vis[dis[y][j].Y] = tim, tmp[++top] = mp(dis[y][j].X + 1, dis[y][j].Y);
}
++j;
}
}
CheckMin(top, 320);
siz[x] = top;
for (int i = 1; i <= siz[x]; ++i) {
dis[x][i] = tmp[i];
}
}
inline void Brute(int s) {
int ans = -1;
f[s] = 0;
if (!ban[s]) {
ans = 0;
}
for (int i = s - 1; i; --i) {
f[i] = -n;
for (auto j : adj[i]) {
if (j <= s) {
CheckMax(f[i], f[j] + 1);
}
}
if (!ban[i]) {
CheckMax(ans, f[i]);
}
}
printf("%d\n", ans);
}
int main() {
#ifdef wxh010910
freopen("d.in", "r", stdin);
#endif
Read(n), Read(m), Read(q);
for (int i = 1, x, y; i <= m; ++i) {
Read(x), Read(y), adj[x].pb(y), rev[y].pb(x);
}
for (int x = 1; x <= n; ++x) {
siz[x] = 1, dis[x][1] = mp(0, x);
for (auto y : rev[x]) {
Merge(x, y);
}
}
for (int i = 1, x, k; i <= q; ++i) {
Read(x), Read(k);
for (int j = 1; j <= k; ++j) {
Read(seq[j]), ban[seq[j]] = true;
}
if (k < 320) {
bool flg = false;
for (int j = 1; j <= siz[x]; ++j) {
if (!ban[dis[x][j].Y]) {
printf("%d\n", dis[x][j].X);
flg = true;
break;
}
}
if (!flg) {
puts("-1");
}
} else {
Brute(x);
}
for (int j = 1; j <= k; ++j) {
ban[seq[j]] = false;
}
}
#ifdef wxh010910
Debug("My Time: %.3lfms\n", (double)clock() / CLOCKS_PER_SEC);
#endif
return 0;
}
