#include using namespace std; struct dsu { public: int csz; dsu() : _n(0) {} dsu(int n) : _n(n), csz(n), parent_or_size(n, -1) {} int merge(int a, int b) { assert(0 <= a && a < _n); assert(0 <= b && b < _n); int x = leader(a), y = leader(b); if (x == y) return x; if (-parent_or_size[x] < -parent_or_size[y]) std::swap(x, y); csz--; parent_or_size[x] += parent_or_size[y]; parent_or_size[y] = x; return x; } bool same(int a, int b) { assert(0 <= a && a < _n); assert(0 <= b && b < _n); return leader(a) == leader(b); } int leader(int a) { assert(0 <= a && a < _n); if (parent_or_size[a] < 0) return a; return parent_or_size[a] = leader(parent_or_size[a]); } int size(int a) { assert(0 <= a && a < _n); return -parent_or_size[leader(a)]; } std::vector> groups() { std::vector leader_buf(_n), group_size(_n); for (int i = 0; i < _n; i++) { leader_buf[i] = leader(i); group_size[leader_buf[i]]++; } std::vector> result(_n); for (int i = 0; i < _n; i++) { result[i].reserve(group_size[i]); } for (int i = 0; i < _n; i++) { result[leader_buf[i]].push_back(i); } result.erase( std::remove_if(result.begin(), result.end(), [&](const std::vector& v) { return v.empty(); }), result.end()); return result; } private: int _n; // root node: -1 * component size // otherwise: parent std::vector parent_or_size; }; int main(){ ios::sync_with_stdio(false); cin.tie(0); int n, m, s, g, u, v; cin >> n >> m >> s >> g; vector> edge(m); vector ban(n); for(int i = 0; i < m; i++){ cin >> u >> v; edge[i] = {--u, --v}; } cin >> u; while(cin >> v) ban[--v] = true; dsu uf(n); for(int i = 0; i < m; i++){ tie(u, v) = edge[i]; if(ban[u] || ban[v]) continue; uf.merge(u, v); } cout << (uf.same(--s, --g) ? "Yes" : "No") << '\n'; }