#include <bits/stdc++.h>
using namespace std;
int main() {
int N, M; cin >> N >> M;
vector<vector<int>> adj(N+1);
for (int i = 0; i < M; i++) {
int a, b; cin >> a >> b;
adj[a].push_back(b);
adj[b].push_back(a);
}
int K; cin >> K;
vector<int> mod(K, -1), rem(N+1, -1), wat(N+1, -1);
for (int i = 0; i < K; i++) {
int l; cin >> l; mod[i] = l;
for (int j = 0; j < l; j++) {
int a; cin >> a;
wat[a] = i;
rem[a] = j;
}
}
vector<set<int>> vis(N+1);
vector<int> been(N+1, 0);
vector<int> best(N+1, -1000000000);
priority_queue<pair<int, int>> pq;
vis[1].insert(0);
pq.push({0, 1});
while (!pq.empty()) {
int a = pq.top().second;
best[a] = max(best[a], pq.top().first);
pq.pop();
if (been[a] > 2) continue;
while (vis[a].size() > 2) vis[a].erase(prev(vis[a].end()));
for (int pos : vis[a]) {
been[a]++;
for (auto x : adj[a]) {
if (wat[x] >= 0 && ((pos+1)%mod[wat[x]] == rem[x])) continue;
if (wat[a] >= 0 && wat[a] == wat[x] && (pos+1)%mod[wat[a]] == rem[a]) continue;
vis[x].insert(pos+1);
pq.push({-pos-1, x});
}
pos++;
if (wat[a] >= 0 && pos%mod[wat[a]] == rem[a]) continue;
for (auto x : adj[a]) {
if (wat[x] >= 0 && ((pos+1)%mod[wat[x]] == rem[x])) continue;
if (wat[a] >= 0 && wat[a] == wat[x] && (pos+1)%mod[wat[a]] == rem[a]) continue;
vis[x].insert(pos+1);
pq.push({-pos-1, x});
}
pos++;
if (wat[a] >= 0 && pos%mod[wat[a]] == rem[a]) continue;
for (auto x : adj[a]) {
if (wat[x] >= 0 && ((pos+1)%mod[wat[x]] == rem[x])) continue;
if (wat[a] >= 0 && wat[a] == wat[x] && (pos+1)%mod[wat[a]] == rem[a]) continue;
vis[x].insert(pos+1);
pq.push({-pos-1, x});
}
}
}
if (best[N] == -1000000000) cout << "impossible\n";
else cout << -best[N] << "\n";
}
