2 1
1 1
2 1
 8 12
-6 2 -3 2 6 -7 1 -5
2 1
5 6
1 6
1 4
8 2
2 7
2 5
8 3
8 4
3 7
7 6
3 1
 10 13
3 4 -3 8 6 4 -5 1 3 -7
9 5
9 2
10 3
1 4
3 5
9 1
6 10
10 4
3 1
2 7
1 6
1 7
7 8
 43 52
-23 -18 -35 21 -12 38 -35 -11 28 -20 27 -5 9 -19 -39 -25 -32 32 -36 28 11 37 1 -25 -22 9 -15 21 25 -39 10 36 -30 -40 22 26 25 -27 -22 -38 -1 18 -13
33 40
31 23
30 26
21 17
6 2
41 19
32 39
32 23
13 14
25 35
31 30
19 32
25 22
34 36
7 40
23 6
40 12
1 3
23 43
36 13
18 33
17 32
7 3
21 34
41 35
20 7
23 1
41 8
25 19
20 29
42 5
40 21
9 37
17 41
30 10
41 18
39 1
20 24
20 4
42 3
20 25
5 16
31 9
42 28
10 11
19 42
31 38
25 2
31 27
17 25
13 15
31 20
 2 1
1 1
1 2
 5 7
4 1 5 3 -1
2 4
5 4
5 2
1 5
1 2
4 1
1 3
 10 12
5 1 1 8 -8 10 -3 -2 1 7
5 3
8 2
10 9
4 6
5 6
4 5
5 10
4 7
8 4
3 1
3 6
6 10
 20 40
-9 -10 -9 15 -3 -5 -17 -10 -6 2 -13 19 10 -15 15 -14 17 0 7 -8
3 17
6 18
15 12
2 5
18 3
16 20
6 17
20 10
10 18
9 12
15 3
6 4
15 16
20 6
20 9
9 4
4 8
14 5
11 7
12 11
3 13
14 19
7 17
16 14
19 7
12 13
14 13
13 11
9 14
13 17
8 19
5 20
2 17
2 16
12 5
8 1
20 3
6 2
5 18
13 8

YES
                                                               1
 NO
 YES
                                                              -7
                                                              10
                                                             -16
                                                               3
                                                              13
                                                               0
                                                               4
                                                               5
                                                               0
                                                              -6
                                                               0
                                                               0
                                                               1
 NO
 YES
                                                               1
 YES
                                                               2
                                                               1
                                                              -1
                                                              -1
                                                               0
                                                               0
                                                               5
 YES
-4
1
1
17
-7
-3
6
-3
-3
5
0
0
 YES
                                                             -30
                                                             -21
                                                             -23
                                                             -10
                                                              21
                                                             -52
                                                               0
                                                               2
                                                               0
                                                              -9
                                                               0
                                                              16
                                                              38
                                                               0
                                                              42
                                                               0
                                                              -1
                                                               7
                                                             -64
                                                              51
                                                               0
                                                               7
                                                              47
                                                               0
                                                               0
                                                               0
                                                              10
                                                               0
                                                             -39
                                                               0
                                                               0
                                                               0
                                                               0
                                                               0
                                                               0
                                                              -9
                                                               0
                                                               0
                                                               0
                                                               0

#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

#define FOR(i, a, b) for (int i = a; i < (b); i++)
#define F0R(i, a) for (int i = 0; i < (a); i++)
#define FORd(i, a, b) for (int i = (b) - 1, i >= a; i--)
#define F0Rd(i, a) for (int i = (a) - 1; i >= 0; i--)

#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()

const int MOD = 1000000007;

void fast_io(){
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);
}
map<pii, int> edgewgts;
vector<pii> edges;
int tot[100005];
set<int> graph[100005];
set<pii> goodedges;
bool col[100005];
int main(){
	int N, M; cin >> N >> M;
	for (int i = 1; i <= N; i++){
		cin >> tot[i];
	}
	for (int i = 1; i <= M; i++){
		int u, v; cin >> u >> v;
		graph[u].insert(v);
		graph[v].insert(u);
		edges.push_back(pii(u, v));
	}
	int rt = 1;
	queue<int> q;
	q.push(rt);
	col[rt] = 0;
	bool vis[100005];
	memset(vis, 0, sizeof(vis));
	while (!q.empty()){
		int v = q.front(); q.pop();
		if (vis[v]) continue; vis[v] = true;
		for (int j: graph[v]){
			if (!vis[j]){
				q.push(j);
				goodedges.insert(pii(j, v));
				vis[j] = true;
				col[j] = (1 - col[v]);
			}
		}
	}
	ll sum = 0;
	for (int i = 1; i <= N; i++){
		if (col[i]) sum += tot[i];
		else{
			sum -= tot[i];
		}
	}
	bool bip = true;
	for (pii e: edges){
		if (col[e.first] == col[e.second]){
			bip = false;
			if (col[e.first]){
				edgewgts[pii(e.first, e.second)] = sum/2;
				edgewgts[pii(e.second, e.first)] = sum/2;
				tot[e.second] -= sum/2;
				tot[e.first] -= sum/2;
				graph[e.first].erase(graph[e.first].find(e.second));
				graph[e.second].erase(graph[e.second].find(e.first));
			}
			else{
				edgewgts[pii(e.second, e.first)] = -sum/2;
				edgewgts[pii(e.first, e.second)] = -sum/2;
				tot[e.second] += sum/2;
				tot[e.first] += sum/2;
				graph[e.first].erase(graph[e.first].find(e.second));
				graph[e.second].erase(graph[e.second].find(e.first));
			}
		}
	}
	if (bip){
		if (sum != 0){
			cout << "NO" << endl;
			return 0;
		}
		else{
			for (int i = 1; i <= N; i++){
				set<int> newedges;
				for (int j: graph[i]){
					if ((goodedges.find(pii(i, j)) != goodedges.end()) or (goodedges.find(pii(j, i)) != goodedges.end())){
						newedges.insert(j);
					}
				}
				graph[i] = newedges;
			}
			cout << "YES" << endl;
			queue<int> q;
			for (int i = 1; i <= N; i++){
				if (graph[i].size() == 1){
					q.push(i);
				}
			}
			while (!q.empty()){
				int i = q.front(); q.pop();
				for (int k: graph[i]){
					edgewgts[pii(i, k)] = tot[i];
					edgewgts[pii(k, i)] = tot[i];
					tot[k] -= tot[i];
					tot[i] = 0;
					graph[k].erase(graph[k].find(i));
					if (graph[k].size() == 1){
						if (k != rt){
							q.push(k);
						}
					}
				}
			}
		}
	}
	else{
		cout << "YES" << endl;
		for (int i = 1; i <= N; i++){
			set<int> newedges;
				for (int j: graph[i]){
					if ((goodedges.find(pii(i, j)) != goodedges.end()) or (goodedges.find(pii(j, i)) != goodedges.end())){
						newedges.insert(j);
					}
				}
				graph[i] = newedges;
			}
			queue<int> q;
			for (int i = 1; i <= N; i++){
				if (graph[i].size() == 1){
					q.push(i);
				}
			}
			while (!q.empty()){
				int i = q.front(); q.pop();
				for (int k: graph[i]){
					edgewgts[pii(i, k)] = tot[i];
					edgewgts[pii(k, i)] = tot[i];
					tot[k] -= tot[i];
					tot[i] = 0;
					graph[k].erase(graph[k].find(i));
					if (graph[k].size() == 1){
						if (k != rt){
							q.push(k);
						}
					}
				}
			}
		
	}
	for (pii k: edges){
		cout << edgewgts[k] << endl;
	}
	
	
	
	
	
}

