ABC 305

void solve() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N, M, K;
    cin >> N >> M >> K;
    vvint graph(N);
    rep(i, M) {
        int u, v;
        cin >> u >> v;
        u--, v--;
        graph[u].push_back(v);
        graph[v].push_back(u);
    }

    vll powers(N, -1);
    rep(i, K) {
        int p, h;
        cin >> p >> h;
        p--;
        powers[p] = h;
    }

    // power, node id
    using P = pair<ll, int>;
    priority_queue<P> pq;
    rep(i, N) {
        if (powers[i] > 0)
            pq.push({powers[i], i});
    }

    while (pq.size()) {
        auto [power, id] = pq.top();
        pq.pop();

        if (powers[id] > power)
            continue;

        for (int nx : graph[id]) {
            if (powers[nx] >= power - 1)
                continue;
            powers[nx] = power - 1;
            pq.push({powers[nx], nx});
        }
    }

    vint ans;
    rep(i, N) {
        if (powers[i] >= 0)
            ans.push_back(i + 1);
    }
    cout << ans.size() << endl;
    print(ans);
}