#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5+10;
const int maxm = 5e5+10;
const int maxl = 20;
const int inf = 2e9+10;
struct T
{
int x, mx, mi;
} tab[maxn][maxl];
typedef pair<int, int> pii;
int a[maxn], cur[maxn];
pii E[maxm];
int edge[maxn], costEdge[maxm];
int pai[maxn], nivel[maxn];
bool mark[maxn];
vector<pii> grafo[maxn];
void dfs(int u, int p)
{
mark[u] = 1;
for (auto pp: grafo[u])
{
int v = pp.first, e = pp.second;
if (mark[v]) continue;
edge[v] = e;
pai[v] = u, nivel[v] = nivel[u]+1;
dfs(v, u);
cur[u] += costEdge[e]/2;
}
if (u != 1)
{
costEdge[edge[u]] = 2*(a[u]-cur[u]);
cur[u] = a[u];
}
}
void init(int n)
{
for (int i = 1; i <= n; i++)
for (int j = 0; j < maxl; j++)
tab[i][j].mx = -inf, tab[i][j].mi = inf;
}
void build(int n)
{
for (int i = 1; i <= n; i++)
{
tab[i][0].x = pai[i];
tab[i][0].mx = tab[i][0].mi = costEdge[edge[i]];
}
for (int j = 1; j < maxl; j++)
{
for (int i = 1; i <= n; i++)
{
tab[i][j].x = tab[tab[i][j-1].x][j-1].x;
tab[i][j].mx = max(tab[i][j-1].mx, tab[tab[i][j-1].x][j-1].mx);
tab[i][j].mi = max(tab[i][j-1].mi, tab[tab[i][j-1].x][j-1].mi);
}
}
}
int lca(int u, int v)
{
if (nivel[u] < nivel[v]) swap(u, v);
for (int i = maxl-1; i >= 0; i--)
if (nivel[u]-(1<<i) >= nivel[v])
u = tab[u][i].x;
if (u == v) return u;
for (int i = maxl-1; i >= 0; i--)
if (tab[u][i].x && tab[v][i].x && tab[u][i].x != tab[v][i].x)
u = tab[u][i].x, v = tab[v][i].x;
return pai[u];
}
pii get(int u, int l)
{
int mx = -inf, mi = inf;
for (int i = maxl-1; i >= 0; i--)
{
if (nivel[u]-(1<<i) >= nivel[l])
{
mx = max(mx, tab[u][i].mx);
mi = min(mi, tab[u][i].mi);
u = tab[u][i].x;
}
}
return {mx, mi};
}
int main(void)
{
int n, m;
scanf("%d %d", &n, &m);
for (int i = 1; i <= n; i++)
scanf("%d", &a[i]);
for (int i = 1; i <= m; i++)
{
int u, v;
scanf("%d %d", &u, &v);
grafo[u].push_back({v, i});
grafo[v].push_back({u, i});
E[i] = {u, v};
}
memset(costEdge, -1, sizeof costEdge);
dfs(1, 0);
if (cur[1] != a[1])
{
printf("0\n");
return 0;
}
init(n);
build(n);
bool ok = 1;
for (int i = 1; i <= m; i++)
{
if (costEdge[i] == -1)
{
int u = E[i].first, v = E[i].second;
int low = lca(u, v), mx = -inf, mi = inf;
pii ans = get(u, low);
mx = max(mx, ans.first); mi = min(mi, ans.second);
ans = get(v, low);
mx = max(mx, ans.first); mi = min(mi, ans.second);
if (mx != 0 || mi != 0)
{
ok = 0;
break;
}
}
}
if (!ok) printf("0\n");
else
{
for (int i = 1; i <= m; i++)
{
if (costEdge[i] == -1) printf("0\n");
else printf("%d\n", costEdge[i]);
}
}
}
