#include "bits/stdc++.h"
using namespace std;
#ifdef duc_debug
#include "bits/debug.h"
#else
#define debug(...)
#endif
const int maxn = 5005;
int n, m, k;
vector<int> g[maxn];
int d[maxn], rev_d[maxn];
long long cnt[maxn], rev_cnt[maxn];
long double f[maxn];
void bfs(int src, int d[], long long cnt[]) {
for(int i = 1; i <= n; ++i) {
d[i] = 1e9;
cnt[i] = 0;
}
queue<int> q;
q.push(src);
d[src] = 0, cnt[src] = 1;
while(!q.empty()) {
int u = q.front();
q.pop();
for(auto v:g[u]) {
if(d[v] > d[u] + 1) {
d[v] = d[u] + 1;
cnt[v] = cnt[u];
q.push(v);
}
else if(d[v] == d[u] + 1) {
cnt[v] += cnt[u];
}
}
}
}
void solve() {
cin >> n >> m;
for(int i = 1; i <= m; ++i) {
int u, v; cin >> u >> v;
++u, ++v;
g[u].push_back(v);
g[v].push_back(u);
}
int q; cin >> q;
while(q--) {
int u, v; cin >> u >> v;
++u, ++v;
bfs(u, d, cnt);
bfs(v, rev_d, rev_cnt);
for(int i = 1; i <= n; ++i) {
if(d[i] + rev_d[i] == d[v]) {
f[i] += (1.0 * cnt[i] * rev_cnt[i]) / cnt[v];
}
}
}
int res = 0;
for(int i = 1; i <= n; ++i) {
if(res == 0 || f[res] < f[i]) res = i;
}
cout << res - 1;
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
solve();
return 0;
}
