/*input
4 3
-1
1
-3
1
1 2
1 3
1 4
*/
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define int long long
#define double long double
#define f first
#define s second
#define mp make_pair
#define pb push_back
#define RE(i,n) for (int i = 1; i <= n; i++)
#define RED(i,n) for (int i = n; i > 0; i--)
#define REPS(i,n) for(int i = 1; (i*i) <= n; i++)
#define REP(i,n) for (int i = 0; i < (int)n; i++)
#define FOR(i,a,b) for (int i = a; i < b; i++)
#define REPD(i,n) for (int i = n-1; i >= 0; i--)
#define FORD(i,a,b) for (int i = a; i >= b; i--)
#define all(v) v.begin(),v.end()
#define pii pair<int,int>
#define vi vector<int>
#define vvi vector<vi>
#define print(arr) for (auto it = arr.begin(); it != arr.end(); ++it) cout << *it << " "; cout << endl;
#define debug(x) cout << x << endl;
#define debug2(x,y) cout << x << " " << y << endl;
#define debug3(x,y,z) cout << x << " " << y << " " << z << endl;
typedef tree<
int,
null_type,
less<int>,
rb_tree_tag,
tree_order_statistics_node_update>
ordered_set;
const int INF = 1e18+1;
const int MOD = 1e9+7;
const double PI = 3.14159265358979323846264338;
int raise(int a,int n,int m = MOD){
if(n == 0)return 1;
if(n == 1)return a;
int x = 1;
x *= raise(a,n/2,m);
x %= m;
x *= x;
x %= m;
if(n%2)x*= a;
x %= m;
return x;
}
int floor1(int n,int k){
if(n%k == 0 || n >= 0)return n/k;
return (n/k)-1;
}
int ceil1(int n,int k){
return floor1(n+k-1,k);
}
const int N = 1e5+1;
vector<pii> adj[N];
int n,m;
int c[N];
int now[N];
int dep[N];
vector<pii> edges;
map<pii,int> val;
bool works = 0;
bool vis[N];
int ans[5*N];
int even = 0;
bool odd = 0;
void dfs(int u,int p,int ind = -1){
if(vis[u])return;
vis[u] = 1;
for(auto v:adj[u]){
if(!vis[v.f])dep[v.f] = dep[u]+1;
else{
if(v.f == p)continue;
if(abs(dep[v.f]-dep[u])%2)odd = 1;
else {
//cout << u << " " << v << endl;
even++;
ans[v.s] = 0;
}
}
dfs(v.f,u,v.s);
}
if(p == -1){
if(!odd)works = (now[u] == c[u]);
return;
}
int diff = c[u]-now[u];
//cout << u 3<< " " << diff << endl;
now[p] += diff;
ans[ind] = 2*diff;
return;
}
void solve(){
cin >> n >> m;
RE(i,n)cin >> c[i];
RE(i,m){
int a,b;
cin >> a >> b;
adj[a].pb({b,i});
adj[b].pb({a,i});
}
dep[1] = 0;
dfs(1,-1);
if(odd or !works or even > 1){
cout << 0 << endl;
return;
}
RE(i,m){
cout << ans[i] << "\n";
}
}
signed main(){
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
//freopen(".in","r",stdin);freopen(".out","w",stdout);
int t = 1;
//cin >> t;
while(t--){
solve();
}
return 0;
}
