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/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;
using namespace std;

#define ff first
#define ss second
#define pb push_back
#define pf push_front
#define mp make_pair
#define popb pop_back
#define popf pop_front
#define all(v) v.begin(), v.end()
#define fori(i, j, k) for (int i = (j); i < (int)(k); i++)
#define forb(i, j, k) for (int i = (j); i >= (int)k; i--)
#define lchild(ind) 2 * ind + 1
#define rchild(ind) 2 * ind + 2
#define bug(val) cout << "# " << val << endl;
#define bugs(val) cout << '_' << val;
#define bugl(val) cout << "## " << val << endl;

template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<int, ll> pil;
typedef pair<ll, int> pli;
typedef pair<ll, ll> pll;
typedef pair<int, pll> pip;
typedef pair<ll, pll> plp;
typedef pair<pll, int> ppi;
typedef pair<pll, ll> ppl;
typedef pair<pll, pll> ppp;
typedef vector<int> vi;
typedef vector<ll> vll;

const int maxn = 1e5 + 1;
const ll inf = 2e18, mod = 1e9 + 7;

int n, m, c[maxn], h[maxn], vert, par[maxn], pare[maxn], VERT, root, edge, ans[maxn];
vector<pii> graph[maxn];
bool visited[maxn], isBip = true;

void checkBip(int u, int prev = -1)
{
	visited[u] = true;
	for (pii i : graph[u])
	{
		if (!visited[i.ff])
		{
			h[i.ff] = h[u] + 1;
			checkBip(i.ff, u);
		}
		else if (i.ff != prev && (h[u] & 1) == (h[i.ff] & 1))
		{
			isBip = false;
			root = i.ff;
			edge = i.ss;
			VERT = u;
		}
	}
}

void dfs(int u, int prev, int prevE)
{
	par[u] = prev;
	pare[u] = prevE;
	visited[u] = true;
	for (pii i : graph[u])
	{
		if (!visited[i.ff])
		{
			h[i.ff] = h[u] + 1;
			dfs(i.ff, u, i.ss);
		}
		else if (i.ff != prev && i.ff == root && (h[u] & 1) == (h[i.ff] & 1))
		{
			vert = i.ff;
			edge = i.ss;
			VERT = u;
		}
	}
	if (prevE != -1)
	{
		ans[prevE] += c[u];
		c[prev] -= c[u];
		c[u] = 0;
	}
}

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);

	cin >> n >> m;
	fori (i, 0, n)
		cin >> c[i];
	int u, v;
	fori (i, 0, m)
	{
		cin >> u >> v;
		u--;
		v--;
		graph[u].pb(mp(v, i));
		graph[v].pb(mp(u, i));
	}
	checkBip(0);
	memset(visited, false, sizeof(visited));
	memset(h, 0, sizeof(h));
	dfs(root, -1, -1);
	if (isBip)
	{
		bool check = true;
		fori (i, 0, n)
			check &= (c[i] == 0);
		if (check)
		{
			cout << "YES" << endl;
			fori (i, 0, m)
				cout << ans[i] << endl;
		}
		else
			cout << "NO" << endl;
	}
	else
	{
		int tmp = 0;
		fori (i, 0, n)
			if (c[i])
				tmp = c[i];
		tmp /= 2;
		ans[edge] += tmp;
		tmp = -tmp;
		for (u = VERT; u != vert; u = par[u])
		{
			ans[pare[u]] += tmp;
			tmp = -tmp;
		}
		cout << "YES" << endl;
		fori (i, 0, m)
			cout << ans[i] << endl;
	}
}
