#pragma GCC optimize(2)
#pragma GCC optimize("Ofast")
#pragma GCC optimize("inline","fast-math","unroll-loops","no-stack-protector")
#pragma GCC diagnostic error "-fwhole-program"
#pragma GCC diagnostic error "-fcse-skip-blocks"
#pragma GCC diagnostic error "-funsafe-loop-optimizations"
#include <bits/stdc++.h>
#define INF 1000000000
#define LINF 1000000000000000000
#define MOD 1000000007
#define mod 998244353
#define F first
#define S second
#define ll long long
#define N 250010
#define M 6000010
#define getchar() (p1==p2&&(p2=(p1=buf)+fread(buf,1,1<<21,stdin),p1==p2)?EOF:*p1++)
using namespace std;
char buf[1 << 23], *p1 = buf, *p2 = buf;
int rint() {
int ret = 0;
char c = getchar();
while (!isdigit(c))
c = getchar();
while (isdigit(c))
ret = ret * 10 + (c - '0'), c = getchar();
return ret;
}
int n, m, q, to[M], pre[M], nxt[M], st[N], sid[N], len[N], idx[N], bel[N], cnt = 0;
ll dist[M];
bool vis[M];
int I(int x, int y) {
return sid[x] + y;
}
ll getnxt(ll t, ll x, ll y) {
if (t % x <= y) {
return (t / x) * x + y;
}
return (t / x + 1) * x + y;
}
void erz(int x, int i) {
if (pre[i] >= 0) {
nxt[pre[i]] = nxt[i];
} else {
st[x] = nxt[i];
}
if (nxt[i] >= 0) {
pre[nxt[i]] = pre[i];
}
return;
}
int main() {
int i, j, x, y;
ll t;
n = rint(), m = rint();
for (i = 0; i < n; i++) {
len[i] = 1;
st[i] = -1;
}
for (i = 0; i < m; i++) {
x = rint() - 1, y = rint() - 1;
to[cnt] = y, nxt[cnt] = st[x], pre[cnt] = -1;
if (st[x] >= 0) {
pre[st[x]] = cnt;
}
st[x] = cnt++;
to[cnt] = x, nxt[cnt] = st[y], pre[cnt] = -1;
if (st[y] >= 0) {
pre[st[y]] = cnt;
}
st[y] = cnt++;
}
q = rint();
for (i = 1; i <= q; i++) {
y = rint();
for (j = 0; j < y; j++) {
x = rint() - 1;
bel[x] = i;
len[x] = y;
idx[x] = j;
}
}
for (i = 0; i < n; i++) {
sid[i + 1] = sid[i] + len[i];
}
memset(dist, 63, sizeof(dist));
priority_queue<pair<ll, pair<int, int>>> pq;
dist[I(0, 0)] = 0;
pq.push(make_pair(0, make_pair(0, 0)));
while (!pq.empty()) {
t = -pq.top().F, x = pq.top().S.F, y = pq.top().S.S;
pq.pop();
if (vis[I(x, y)]) {
continue;
}
vis[I(x, y)] = true;
if ((y + 1) % len[x] != idx[x] && dist[I(x, (y + 1) % len[x])] > t + 1) {
dist[I(x, (y + 1) % len[x])] = t + 1;
pq.push(make_pair(-t - 1, make_pair(x, (y + 1) % len[x])));
}
for (i = st[x]; i >= 0; i = nxt[i]) {
int u = to[i];
if (len[u] == 1) {
if (dist[I(u, 0)] > t + 1) {
dist[I(u, 0)] = t + 1;
pq.push(make_pair(-t - 1, make_pair(u, 0)));
}
erz(x, i);
continue;
}
if (len[x] == 1) {
if ((t + 1) % len[u] != idx[u] && dist[I(u, (t + 1) % len[u])] > t + 1) {
dist[I(u, (t + 1) % len[u])] = t + 1;
pq.push(make_pair(-t - 1, make_pair(u, (t + 1) % len[u])));
}
ll v0 = getnxt(t, len[u], idx[u]);
if ((v0 + 1) % len[u] != idx[u] && dist[I(u, (v0 + 1) % len[u])] > v0 + 1) {
dist[I(u, (v0 + 1) % len[u])] = v0 + 1;
pq.push(make_pair(-v0 - 1, make_pair(u, (v0 + 1) % len[u])));
}
continue;
}
if (bel[x] == bel[u] && idx[u] == (idx[x] + 1) % len[x]) {
if (dist[I(u, (y + 1) % len[x])] > t + 1) {
dist[I(u, (y + 1) % len[x])] = t + 1;
pq.push(make_pair(-t - 1, make_pair(u, (y + 1) % len[x])));
}
continue;
}
if (bel[x] == bel[u] && idx[x] == (idx[u] + 1) % len[x]) {
if (idx[u] != (y + 1) % len[x] && idx[u] != y) {
dist[I(u, (y + 1) % len[x])] = t + 1;
pq.push(make_pair(-t - 1, make_pair(u, (y + 1) % len[x])));
}
continue;
}
if ((t + 1) % len[u] != idx[u] && dist[I(u, (t + 1) % len[u])] > t + 1) {
dist[I(u, (t + 1) % len[u])] = t + 1;
pq.push(make_pair(-t - 1, make_pair(u, (t + 1) % len[u])));
}
ll v0 = getnxt(t + 1, len[u], idx[u]);
if (v0 % len[x] != idx[x]) {
if ((v0 + 1) % len[u] != idx[u] && dist[I(u, (v0 + 1) % len[u])] > v0 + 1) {
dist[I(u, (v0 + 1) % len[u])] = v0 + 1;
pq.push(make_pair(-v0 - 1, make_pair(u, (v0 + 1) % len[u])));
}
erz(x, i);
continue;
}
ll v1 = getnxt(v0, len[x], y), v2 = getnxt(v1, len[u], idx[u]);
if ((v1 + 1) % len[u] != idx[u] && dist[I(u, (v1 + 1) % len[u])] > v1 + 1) {
dist[I(u, (v1 + 1) % len[u])] = v1 + 1;
pq.push(make_pair(-v1 - 1, make_pair(u, (v1 + 1) % len[u])));
}
if (v2 % len[x] != idx[x]) {
if ((v2 + 1) % len[u] != idx[u] && dist[I(u, (v2 + 1) % len[u])] > v2 + 1) {
dist[I(u, (v2 + 1) % len[u])] = v2 + 1;
pq.push(make_pair(-v2 - 1, make_pair(u, (v2 + 1) % len[u])));
}
}
}
}
if (dist[I(n - 1, 0)] > LINF) {
puts("impossible");
} else {
printf("%lld\n", dist[I(n - 1, 0)]);
}
return 0;
}
