#include <bits/stdc++.h>
using namespace std;
#define io ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define ALL(x) x.begin(),x.end()
#define SZ(x) x.size()
#define PB push_back
#define MP make_pair
#define F first
#define S second
typedef long long LL;
typedef vector<int> VI;
typedef pair<int,int> PI;

const int N=1e5+1;
vector<VI> g;
int n,h,d[N],f,x;
VI ans;
bool vis[N];

void dfs(int u,int v) {
   if(!f)
      return;
   if(v && SZ(g[u]) > 2) {
      f = 0;
      return;
   }
   vis[u] = true;
   for(int i = 0; i < SZ(g[u]); i++) {
      if(!vis[g[u][i]])
         dfs(g[u][i],1);
   }
}

void solve(int u) {
   vis[u] = 1;
   if(SZ(g[u]) == 1 && u != x)
      ans.PB(u);
   for(int i = 0; i < SZ(g[u]); i++) {
      if(!vis[g[u][i]])
         solve(g[u][i]);
   }
}

int main() {
   io
   cin >> n;
   g.clear();
   g.resize(n+1);
   h = 1;
   for(int i = 0; i < n-1; i++) {
      int u,v;
      cin >> u >> v;
      g[u].PB(v); d[u]++;
      g[v].PB(u); d[v]++;
      if(d[u] > d[h])
         h = u;
      if(d[v] > d[h])
         h = v;
   }
   f = 1;
   x = -1;
   dfs(h,0);
   if(f)
      x = h;
   if(x == -1)
      return 0*puts("No");
   memset(vis,0,sizeof(vis));
   solve(x);
   puts("Yes");
   cout << SZ(ans) << "\n";
   for(int i = 0; i < SZ(ans); i++)
      cout << x << " " << ans[i] << "\n";
}