#include <bits/stdc++.h>
using ll = long long;
using std::cin;
using std::cout;
using std::endl;
std::mt19937 rnd(std::chrono::steady_clock::now().time_since_epoch().count());
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
const int inf = (int)1e9 + 7;
const long long INF = 1LL << 60;

template<typename T>
struct Dinic {
    struct edge {
        int to;
        T cap;
        int rev;
        bool isrev;
        int idx;
        edge(int _to, T _cap, int _rev, bool _isrev, int _idx) :to(_to), cap(_cap), rev(_rev), isrev(_isrev), idx(_idx) {}
    };
    std::vector<std::vector<edge>> g;
    std::vector<int> min_cost, iter;
    T INF;
    Dinic(int n, T INF) :g(n), INF(INF) {}

    void add_edge(int from, int to, T cap, int idx = -1) {
        g[from].emplace_back(to, cap, (int)g[to].size(), false, idx);
        g[to].emplace_back(from, 0, (int)g[from].size() - 1, true, idx);
    }

    bool bfs(int s, int t) {
        min_cost.assign(g.size(), -1);
        std::queue<int> q;
        q.emplace(s);
        min_cost[s] = 0;
        while (!q.empty() && min_cost[t] == -1) {
            int cur = q.front();
            q.pop();
            for (auto& e : g[cur]) {
                if (e.cap > 0 && min_cost[e.to] == -1) {
                    min_cost[e.to] = min_cost[cur] + 1;
                    q.push(e.to);
                }
            }
        }
        return min_cost[t] != -1;
    }

    T dfs(int idx, const int t, T flow) {
        if (idx == t) return flow;
        for (int& i = iter[idx]; i < (int)g[idx].size(); i++) {
            edge& e = g[idx][i];
            if (e.cap > 0 && min_cost[idx] < min_cost[e.to]) {
                T d = dfs(e.to, t, std::min(flow, e.cap));
                if (d > 0) {
                    e.cap -= d;
                    g[e.to][e.rev].cap += d;
                    return d;
                }
            }
        }
        return 0;
    }

    T max_flow(int s, int t) {
        T flow = 0;
        while (bfs(s, t)) {
            iter.assign(g.size(), 0);
            T f = 0;
            while ((f = dfs(s, t, INF)) > 0) flow += f;
        }
        return flow;
    }

    void output() {
        for(int i = 0; i < (int)g.size(); i++) {
          for(auto &e : g[i]) {
            if(e.isrev) continue;
            auto &rev_e = g[e.to][e.rev];
            cout << i << "->" << e.to << " (flow: " << rev_e.cap << "/" << e.cap + rev_e.cap << ")" << endl;
          }
        }
    }
};
void solve()
{
  int n; cin >> n;
  Dinic<int> g(n * 2 + 2, inf);
  const int s = n * 2;
  const int t = s + 1;
  for (int i = 0; i < n; ++i)
  {
    int a, b; cin >> a >> b;
    a -= 1, b -= 1;
    g.add_edge(i, n + a, 1);
    g.add_edge(i, n + b, 1);
  }
  for (int i = 0; i < n; ++i)
  {
    g.add_edge(s, i, 1);
    g.add_edge(i + n, t, 1);
  }
  const int max_flow = g.max_flow(s, t);
  if(max_flow == n)
  {
    cout << "Yes" << "\n";
    for(int i = 0; i < n; i++) {
      for(auto &e : g.g[i]) {
        if(e.isrev) continue;
        auto &rev_e = g.g[e.to][e.rev];
        if(rev_e.cap == 1)
        {
          const int to = e.to - n;
          cout << to + 1 << "\n";
        }
        // cout << i << "->" << e.to << " (flow: " << rev_e.cap << "/" << e.cap + rev_e.cap << ")" << endl;
      }
    }
  }
  else
  {
    cout << "No" << "\n";
  }
}
int main()
{
  std::cin.tie(nullptr);
  std::ios::sync_with_stdio(false);

  int kkt = 1; 
  // cin >> kkt;
  while(kkt--)
    solve();
  return 0;
  
}