#include #include #include #include #include #include #include #include #include namespace atcoder { namespace internal { template struct csr { std::vector start; std::vector elist; explicit csr(int n, const std::vector>& edges) : start(n + 1), elist(edges.size()) { for (auto e : edges) { start[e.first + 1]++; } for (int i = 1; i <= n; i++) { start[i] += start[i - 1]; } auto counter = start; for (auto e : edges) { elist[counter[e.first]++] = e.second; } } }; } // namespace internal } // namespace atcoder namespace atcoder { namespace internal { struct scc_graph { public: explicit scc_graph(int n) : _n(n) {} int num_vertices() { return _n; } void add_edge(int from, int to) { edges.push_back({from, {to}}); } std::pair> scc_ids() { auto g = csr(_n, edges); int now_ord = 0, group_num = 0; std::vector visited, low(_n), ord(_n, -1), ids(_n); visited.reserve(_n); auto dfs = [&](auto self, int v) -> void { low[v] = ord[v] = now_ord++; visited.push_back(v); for (int i = g.start[v]; i < g.start[v + 1]; i++) { auto to = g.elist[i].to; if (ord[to] == -1) { self(self, to); low[v] = std::min(low[v], low[to]); } else { low[v] = std::min(low[v], ord[to]); } } if (low[v] == ord[v]) { while (true) { int u = visited.back(); visited.pop_back(); ord[u] = _n; ids[u] = group_num; if (u == v) break; } group_num++; } }; for (int i = 0; i < _n; i++) { if (ord[i] == -1) dfs(dfs, i); } for (auto& x : ids) { x = group_num - 1 - x; } return {group_num, ids}; } std::vector> scc() { auto ids = scc_ids(); int group_num = ids.first; std::vector counts(group_num); for (auto x : ids.second) counts[x]++; std::vector> groups(ids.first); for (int i = 0; i < group_num; i++) { groups[i].reserve(counts[i]); } for (int i = 0; i < _n; i++) { groups[ids.second[i]].push_back(i); } return groups; } private: int _n; struct edge { int to; }; std::vector> edges; }; } // namespace internal } // namespace atcoder namespace atcoder { struct two_sat { public: two_sat() : _n(0), scc(0) {} explicit two_sat(int n) : _n(n), _answer(n), scc(2 * n) {} void add_clause(int i, bool f, int j, bool g) { assert(0 <= i && i < _n); assert(0 <= j && j < _n); scc.add_edge(2 * i + (f ? 0 : 1), 2 * j + (g ? 1 : 0)); scc.add_edge(2 * j + (g ? 0 : 1), 2 * i + (f ? 1 : 0)); } bool satisfiable() { auto id = scc.scc_ids().second; for (int i = 0; i < _n; i++) { if (id[2 * i] == id[2 * i + 1]) return false; _answer[i] = id[2 * i] < id[2 * i + 1]; } return true; } std::vector answer() { return _answer; } private: int _n; std::vector _answer; internal::scc_graph scc; }; } // namespace atcoder using namespace std; using namespace atcoder; int main() { ios_base::sync_with_stdio(false); cin.tie(nullptr); const int MX = 1000000; vector pr(MX); for (int i = 2; i * i < MX; i++) { if (!pr[i]) { for (int j = i * i; j < MX; j += i) { pr[j] = true; } } } int n; cin >> n; vector> a(n, vector(2)); two_sat ts(n); auto is_prime = [&](int u, int v) { return !pr[stoi(to_string(u) + to_string(v))]; }; for (int i = 0; i < n; i++) { cin >> a[i][0] >> a[i][1]; for (int j = 0; j <= i; j++) { for (int g = 0; g < 2; g++) { for (int h = 0; h < 2; h++) { if (is_prime(a[i][g], a[j][1 - h]) || is_prime(a[j][h], a[i][1 - g])) { ts.add_clause(i, 1 - g, j, 1 - h); } } } } } cout << (ts.satisfiable() ? "Yes" : "No"); }