#include <cstdlib>
#include <cmath>
#include <climits>
#include <cfloat>
#include <map>
#include <set>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <cstdio>
#include <cstring>
#include <iterator>
#include <bitset>
#include <unordered_set>
#include <unordered_map>
#include <fstream>
#include <iomanip>
#include <cassert>
//#include <utility>
//#include <memory>
//#include <functional>
//#include <deque>
//#include <cctype>
//#include <ctime>
//#include <numeric>
//#include <list>
//#include <iomanip>

//#if __cplusplus >= 201103L
//#include <array>
//#include <tuple>
//#include <initializer_list>
//#include <forward_list>
//
//#define cauto const auto&
//#else

//#endif

using namespace std;


typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vint;
typedef vector<vector<int> > vvint;
typedef vector<long long> vll, vLL;
typedef vector<vector<long long> > vvll, vvLL;

#define VV(T) vector<vector< T > >

template <class T>
void initvv(vector<vector<T> > &v, int a, int b, const T &t = T()){
    v.assign(a, vector<T>(b, t));
}

template <class F, class T>
void convert(const F &f, T &t){
    stringstream ss;
    ss << f;
    ss >> t;
}

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define reep(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n) reep((i),0,(n))
#define ALL(v) (v).begin(),(v).end()
#define PB push_back
#define F first
#define S second
#define mkp make_pair
#define RALL(v) (v).rbegin(),(v).rend()
#define DEBUG
#ifdef DEBUG
#define dump(x)  cout << #x << " = " << (x) << endl;
#define debug(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;
#else
#define dump(x) 
#define debug(x) 
#endif

#define MOD 1000000007LL
#define EPS 1e-8
#define INF 0x3f3f3f3f
#define INFL 0x3f3f3f3f3f3f3f3fLL
#define maxs(x,y) x=max(x,y)
#define mins(x,y) x=min(x,y)

vvint vv;
int n,u,v;
pii no;
int dfs(int x,int y,vint &cnt){
	int t=0;
	for(int p:vv[x]){
		if(p==y) continue;
		t+=dfs(p,x,cnt);
	}
	return cnt[x]=t+1;
}

bool dfs2(int pos,int num,int pre=-1,int c=0){
	int a=0,b;
	if(pos==c) return false;
	rep(i,vv[pos].size()){
		if(vv[pos][i]==pre) continue;
		pii tmp=minmax(pos,vv[pos][i]);
		if(no==tmp) continue;
		a++;
		b=vv[pos][i];
	}
	// cout<<pos<<" "<<num<<" "<<pre<<" "<<a<<" "<<b<<endl;
	if(num+1==n/2){
		if(a==0) return true;
		else return false;
	}
	else{
		if(a==1){
			return dfs2(b,num+1,pos,c);
		}
		else return false;
	}
}


void mainmain(){
	cin>>n>>u>>v;
	if(n&1){
		cout<<"No"<<endl;
		return;
	}
	u--;
	v--;
	vv=vvint(n);
	rep(i,n-1){
		int a,b;
		cin>>a>>b;
		a--;
		b--;
		vv[a].PB(b);
		vv[b].PB(a);
	}
	vint cnt(n);
	dfs(u,-1,cnt);
	int pos=-1;
	rep(i,n){
		// cout<<i<<" "<<cnt[i]<<endl;
		if(cnt[i]==n/2){
			pos=i;
		}
	}
	if(pos==-1){
		cout<<"No"<<endl;
		return;
	}
	rep(i,vv[pos].size()){
		int p=vv[pos][i];
		if(cnt[pos]<cnt[p]){
			no=minmax(pos,p);
		}
	}
	// cout<<no.F<<" "<<no.S<<endl;
	bool ok=true;
	ok&=dfs2(u,0,-1,v);
	ok&=dfs2(v,0,-1,u);
	if(ok) cout<<"Yes"<<endl;
	else cout<<"No"<<endl;
	return;
}


signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout<<fixed<<setprecision(20);
    mainmain();
}

Measured memory_bytes: 16600