#include "bits/stdc++.h"
using namespace std;
#define ln "\n"
#define pb push_back
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()
#define sz(x) ((int)(x).size())
#define int long long
const int MOD = 1e9 + 7;
const int inf = 2e18;
const int N = 5005;
int n, m, k, f[N][N], cnt[N][N];
pair<int, int> d[N];
double h[N];
vector<int> g[N];
void bfs(int st) {
for(int i = 1; i <= n; i++) f[st][i] = inf;
f[st][st] = 0;
cnt[st][st] = 1;
queue<int> q;
q.push(st);
while(sz(q)) {
int u = q.front(); q.pop();
for(int v : g[u]) {
if(f[st][v] > f[st][u] + 1) {
f[st][v] = f[st][u] + 1;
cnt[st][v] = cnt[st][u];
q.push(v);
} else if(f[st][v] == f[st][u] + 1) {
cnt[st][v] += cnt[st][u];
}
}
}
}
bool mark[N];
signed main() {
cin.tie(0) -> sync_with_stdio(0);
cin >> n >> m;
for(int i = 1; i <= m; i++) {
int u, v; cin >> u >> v;
u++, v++;
g[u].pb(v);
g[v].pb(u);
}
cin >> k;
for(int i = 1; i <= k; i++) {
cin >> d[i].fi >> d[i].se;
d[i].fi++, d[i].se++;
}
int ans = 0;
for(int i = 1; i <= n; i++) {
for(int j = 1; j <= k; j++) {
int a = d[j].fi, b = d[j].se;
if(mark[a] == 0) bfs(a);
if(mark[b] == 0) bfs(b);
mark[a] = mark[b] = 1;
if(f[a][i] + f[b][i] == f[a][b]) {
int sus = cnt[a][i] * cnt[b][i];
h[i] += (double) sus / cnt[a][b];
}
}
if(h[i] > h[ans]) {
ans = i;
}
}
cout << ans - 1;
}
