#include <bits/stdc++.h>
#define ll long long
#define rep(i, n, m) for (ll i = n; i <= m; i ++)
#define rrep(i, n, m) for (ll i = n; i >= m; i --)
using namespace std;
const long long N = 2e5 + 5;
struct edge {
int u, v;
ll val;
int other(int x) {
return u ^ v ^ x;
}
} E[3 * N];
vector <int> d[N];
ll a[N], deg[N], n, m;
bool vis[N];
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
cin >> n >> m;
rep(i, 1, n) cin >> a[i];
rep(i, 1, m) {
cin >> E[i].u >> E[i].v;
d[E[i].u].push_back(i);
d[E[i].v].push_back(i);
deg[E[i].u] ++; deg[E[i].v] ++;
E[i].val = 0;
}
int lef = n;
queue <int> q;
rep(i, 1, n) if (d[i].size() == 1)
q.push(i), deg[i] = 0, vis[i] = true;
if (n == 2) {
if (a[1] == a[2]) {
cout << 2 * a[1] << '\n';
return 0;
} else {
cout << 0 << '\n';
return 0;
}
}
int lst = -1;
while (q.size()) {
int u = q.front(); q.pop();
lst = u;
lef --;
vis[u] = true;
for (int i: d[u]) {
int v = E[i].other(u);
if (vis[v]) continue;
E[i].val += 2 * a[u];
a[v] -= a[u];
-- deg[v];
if (deg[v] == 1 || (lef == 1 && deg[v] == 0)) {
q.push(v);
}
}
}
if (a[lst])
cout << 0 << '\n';
else
rep(i, 1, m) cout << E[i].val << '\n';
return 0;
}
