#include <iostream>
#include <vector>
#include <map>
#include <queue>
using namespace std;
const long long MAXN = 5e5+5;
vector<long long> v1[MAXN];
long long p[MAXN];
vector<long long> leaves;
long long val[MAXN];
map<pair<long long,long long>,long long> m1;
long long node[MAXN];
long long ans[MAXN];
void dfs(long long curr,long long par){
p[curr] = par;
for(long long x:v1[curr]){
if(x!=par){
dfs(x,curr);
}
}
if(v1[curr].size() == 1 && curr!=1){
leaves.push_back(curr);
}
}
int main(){
long long n,m;
cin>>n>>m;
for(long long i=1;i<=n;i++){
cin>>val[i];
}
for(long long i=1;i<n;i++){
long long x,y;
cin>>x>>y;
v1[x].push_back(y);
v1[y].push_back(x);
m1[make_pair(x,y)] = i;
m1[make_pair(y,x)] = i;
}
dfs(1,0);
queue<long long> q1;
for(long long x:leaves){
q1.push(x);
}
while(!q1.empty()){
long long curr =q1.front();
q1.pop();
if(curr == 0){
break;
}
long long edgew = (val[curr]-node[curr])*2;
node[p[curr]]+=val[curr]-node[curr];
ans[m1[make_pair(p[curr],curr)]] = edgew;
q1.push(p[curr]);
}
if(node[0]){
cout<<0<<endl;
return 0;
}
for(long long i=1;i<n;i++){
cout<<ans[i]<<endl;
}
}
