#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define N 600005
#define ff first
#define ss second
#define pb push_back
#define sz(s) (int)s.size()
ll n, m, par[N], a[N], vis[N], c[N], sum, tr;
vector <ll> v[N], e;
vector <pair <ll,ll>> ans;
map <pair<ll,ll>,ll> vip;
void solve(int x) {
vis[x] = 1;
for(auto i : v[x]) {
if(!vis[i]) {
par[i] = x;
solve(i);
if(!c[i]) {
ans.pb({vip[{i,x}],a[i]});
// cout << x << " " << i<< " " << a[x] << " " << a[i]<< '\n';
a[x] -= a[i];
}
continue;
}
if(i != par[x] && c[i] == 0) {
int p = x;
e.pb(i);
while(p != i) {
e.pb(p);
c[p] = 1;
p = par[p];
}
e.pb(i);
// reverse(e.begin(),e.end());
c[i] = 1;
if(sz(e) % 2) {
cout << "0\n";
exit(0);
}
}
}
}
int main () {
ios::sync_with_stdio(0);cin.tie(0);
cin >> n >> m;
for(int i = 1;i <= n; i++) {
cin >> a[i];
par[i] = i;
}
for(int i = 1;i <= m; i++) {
ll x, y;
cin >> x >> y;
v[x].pb(y);
v[y].pb(x);
vip[{x,y}] = i;
vip[{y,x}] = i;
}
if(n < m) {
cout << '0' << '\n';
return 0;
}
solve(1);
bool t = 0;
for(int i = 0; i < sz(e) - 1; i++) {
if(!t)sum += a[e[i]];
else sum -= a[e[i]];
t = 1 - t;
}
reverse(e.begin(),e.end());
sum /= 2;
for(int i = 0;i<sz(e)- 1;i++) {
ans.pb({vip[{e[i],e[i+1]}],sum});
sum = a[e[i+1]] - sum;
}
sort(ans.begin(),ans.end());
for(auto i:ans) {
cout << i.ss * 2 << '\n';
}
}
