#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 10;
int n, ch, x, y;
vector<int> path[maxn];
vector<int> ans;
int main() {
  scanf("%d", &n);
  for (int i = 1; i < n; i++) {
    scanf("%d%d", &x, &y);
    path[x].push_back(y);
    path[y].push_back(x);
  }
  ch = 0;
  for (int i = 1; i <= n; i++)
    if (path[i].size() > 2) {
      if (ch == 0)
        ch = i;
      else {
        puts("No");
        return 0;
      }
    }
  if (ch == 0) {
    puts("Yes");
    puts("1");
    x = y = 0;
    for (int i = 1; i <= n; i++)
      if (path[i].size() == 1) {
        if (x == 0)
          x = i;
        else
          y = i;
      }
    printf("%d %d\n", x, y);
  } else {
    puts("Yes");
    ans.clear();
    for (int i = 1; i <= n; i++)
      if (path[i].size() == 1) ans.push_back(i);
    printf("%d\n", ans.size());
    for (int i = 0; i < ans.size(); i++) printf("%d %d\n", ch, ans[i]);
  }
  return 0;
}
