#include <iostream>
#include <cstring>
#include <cassert>
#include <vector>
typedef long long llong;
const int MAXN = 100000 + 10;
const int MAXSQ = 320;
const int INF = 1e9;
std::vector <int> g[MAXN];
std::pair < int,int > dp[MAXN][MAXSQ];
std::pair < int,int > buff[MAXSQ];
bool inDP[MAXN];
int bucketSize;
bool bl[MAXN];
bool bl2[MAXN];
int dp2[MAXN];
int n, m, q;
void calcDP(int node)
{
bl2[node] = true;
std::fill(dp[node]+1, dp[node]+bucketSize, std::make_pair(0, -INF));
dp[node][0] = {node, 0};
for (int i : g[node])
{
if (!bl2[i]) calcDP(i);
int lp = 0, rp = 0;
for (int j = 0 ; j < bucketSize ; ++j)
{
dp[i][j].second++;
}
for (int j = 0 ; j < bucketSize ; ++j)
{
while (dp[node][lp].first != 0 && bl[dp[node][lp].first]) lp++;
while (dp[i][rp].first != 0 && bl[dp[i][rp].first]) rp++;
if (dp[node][lp].second > dp[i][rp].second)
{
bl[dp[node][lp].first] = true;
buff[j] = dp[node][lp];
lp++;
} else
{
bl[dp[i][rp].first] = true;
buff[j] = dp[i][rp];
rp++;
}
}
for (int j = 0 ; j < bucketSize ; ++j)
{
bl[dp[node][j].first] = false;
bl[dp[i][j].first] = false;
dp[node][j] = buff[j];
dp[i][j].second--;
}
}
}
int f(int node)
{
if (bl2[node]) return dp2[node];
bl2[node] = true;
dp2[node] = -INF;
if (!bl[node]) dp2[node] = 0;
for (int i : g[node])
{
dp2[node] = std::max(dp2[node], f(i) + 1);
}
return dp2[node];
}
void solve()
{
bucketSize = 317;
for (int i = 1 ; i <= n ; ++i)
{
if (bl2[i]) continue;
calcDP(i);
}
std::vector <int> curr;
for (int i = 1 ; i <= q ; ++i)
{
int node, count;
std::cin >> node >> count;
curr.clear();
curr.resize(count + 1);
for (int j = 1 ; j <= count ; ++j)
{
std::cin >> curr[j];
bl[curr[j]] = true;
}
if (count <= bucketSize-1)
{
for (int i = 0 ; i <= bucketSize ; ++i)
{
if (bl[dp[node][i].first]) continue;
if (dp[node][i].second < 0) std::cout << -1 << '\n';
else std::cout << dp[node][i].second << '\n';
break;
}
} else
{
memset(bl2, false, sizeof(bl2));
int res = f(node);
if (res < 0) std::cout << -1 << '\n';
else std::cout << res << '\n';
}
for (int j = 1 ; j <= count ; ++j)
{
bl[curr[j]] = false;
}
}
}
void read()
{
int x, y;
std::cin >> n >> m >> q;
for (int i = 1 ; i <= m ; ++i)
{
std::cin >> x >> y;
g[y].push_back(x);
}
}
void fastIO()
{
std::ios_base :: sync_with_stdio(0);
std::cout.tie(nullptr);
std::cin.tie(nullptr);
}
int main()
{
fastIO();
read();
solve();
return 0;
}
/*
5 6 1
1 2
2 4
3 4
1 3
3 5
4 5
4 1 1
5 2 2 3
2 3 1 4 5
*/
