// g++ temp.cpp
// C++ includes used for precompiling -*- C++ -*-

// Copyright (C) 2003-2013 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/** @file stdc++.h
 *  This is an implementation file for a precompiled header.
 */

// 17.4.1.2 Headers

// C
//#ifndef _GLIBCXX_NO_ASSERT
#include <cassert>
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
/*
//#if __cplusplus >= 201103L
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>
*/

// C++
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
/*
//#if __cplusplus >= 201103L
#include <array>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
*/
using namespace std;
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
#define zero(x) (((x)>0?(x):-(x))<eps)
typedef vector<int> VI;
typedef long long LL;
typedef pair<int,int>PII;
const double eps=1e-6;
const double pi=acos(-1.0);
const LL mod=1e18+7;
const int INF=0x3f3f3f3f;
//LL powmod(LL a,LL b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
VI v[100010];
int a[100010];
int vis[100010];
int dfs(int x){
    vis[x]=1;
    if(SZ(v[x])==1) return a[x];
    int tmp,sum=a[x]*2;
    for(auto i:v[x]){
        if(!vis[i]){
            tmp=dfs(i);
            sum-=tmp;
            if(sum<0||tmp==-1||tmp>a[x]) return -1;
        }
    }
    if(sum>a[x]) return -1;
    return sum;
}
int main(){
//    freopen("in.in","r",stdin);
//    freopen("out.out",";w",stdout);
    int n,x,y;
    cin>>n;
    for(int i=1;i<=n;i++) cin>>a[i];
    for(int i=1;i<n;i++){
        cin>>x>>y;
        v[x].pb(y);
        v[y].pb(x);
    }
    if(n==2) return 0*puts(a[1]==a[2]?"YES":"NO");
    int j=1;
    while(SZ(v[j])==1) j++;
    puts(dfs(j)?"NO":"YES");
    return 0;
}
/*
 
*/

Measured memory_bytes: 10496