#include <bits/stdc++.h>
#define ll long long
#define sz(x) (int)(x).size()
#define pii pair<int,int>
using namespace std;
const int MAXN = 100001;
vector<pii> edges[MAXN];
int score[MAXN];
ll cur[MAXN];
int ans[5*MAXN];
void dfs(int c, int p, int x)
{
for (pii i : edges[c])
if (i.first != p)
{
dfs(i.first, c, i.second);
cur[c]+=ans[i.second];
}
if (c!=1)
{
ans[x]=score[c]-cur[c];
cur[c]=score[c];
}
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0);
int n,m,u,v;
cin>>n>>m;
for (int i = 1; i <= n; ++i)
cin>>score[i];
for (int i = 0; i < m; ++i)
{
cin>>u>>v;
edges[u].push_back({v,i});
edges[v].push_back({u,i});
}
dfs(1,0,0);
if (score[1]!=cur[1])
{
cout<<"0\n";
return 0;
}
for (int i=0;i<m;++i)
cout<<ans[i]*2<<"\n";
return 0;
}
