/** * @FileName a.cpp * @Author kanpurin * @Created 2021.08.07 06:06:48 **/ #include "bits/stdc++.h" using namespace std; typedef long long ll; struct Dinic { private: struct edge { int to; ll cap; int rev; bool isrev; int idx; }; vector< vector< edge > > graph; vector< int > min_cost, iter; bool bfs(int s, int t) { min_cost.assign(graph.size(), -1); queue< int > que; min_cost[s] = 0; que.push(s); while (!que.empty() && min_cost[t] == -1) { int p = que.front(); que.pop(); for (auto &e : graph[p]) { if (e.cap > 0 && min_cost[e.to] == -1) { min_cost[e.to] = min_cost[p] + 1; que.push(e.to); } } } return min_cost[t] != -1; } ll dfs(int idx, const int t, ll flow) { if (idx == t) return flow; for (int &i = iter[idx]; i < graph[idx].size(); i++) { edge &e = graph[idx][i]; if (e.cap > 0 && min_cost[idx] < min_cost[e.to]) { ll d = dfs(e.to, t, min(flow, e.cap)); if (d > 0) { e.cap -= d; graph[e.to][e.rev].cap += d; return d; } } } return 0; } public: Dinic(int V) : graph(V) {} void add_edge(int from, int to, ll cap, int idx = -1) { graph[from].push_back({to, cap, (int)graph[to].size(), false, idx}); graph[to].push_back({from, 0, (int)graph[from].size() - 1, true, idx}); } ll max_flow(int s, int t) { ll flow = 0; while (bfs(s, t)) { iter.assign(graph.size(), 0); ll f = 0; while ((f = dfs(s, t, 1e9 + 6)) > 0) flow += f; } return flow; } void output() { for (int i = 0; i < graph.size(); i++) { for (auto &e : graph[i]) { if (e.isrev) continue; auto &rev_e = graph[e.to][e.rev]; cout << i << "->" << e.to << " (flow: " << rev_e.cap << "/" << e.cap + rev_e.cap << ")" << endl; } } } int ans(int v) { for (auto &e : graph[v]) { if (e.isrev) continue; auto &rev_e = graph[e.to][e.rev]; if (rev_e.cap == 1) return e.to; } return -1; } }; int main() { int n;cin >> n; vector a(n),b(n); Dinic g(n*2+2); int s = n*2, t = n*2+1; for (int i = 0; i < n; i++) { cin >> a[i] >> b[i]; g.add_edge(i,n+a[i]-1,1); g.add_edge(i,n+b[i]-1,1); g.add_edge(s,i,1); g.add_edge(n+i,t,1); } if (g.max_flow(s,t) != n) { puts("No"); } else { puts("Yes"); for (int i = 0; i < n; i++) { cout << g.ans(i)-n+1 << endl; } } return 0; }