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

/***********************************************************
  * Author: Hany01
  * Task: e
  * E-Mail: hany01@foxmail.com
***********************************************************/

#include<bits/stdc++.h>

using namespace std;

typedef long long LL;
typedef long double LD;
typedef pair<int, int> PII;
#define For(i, j, k) for (register int i = (j), i##_end_ = (k); i <= i##_end_; ++ i)
#define Fordown(i, j, k) for (register int i = (j), i##_end_ = (k); i >= i##_end_; -- i)
#define Rep(i, k) for (register int i = 0, i##_end_ = (k); i < i##_end_; ++ i)
#define Set(a, b) memset(a, b, sizeof(a))
#define Cpy(a, b) memcpy(a, b, sizeof(a))
#define X first
#define Y second
#define PB(a) push_back(a)
#define MP(a, b) make_pair(a, b)
#define ALL(a) (a).begin(), (a).end()
#define SZ(a) ((int)(a).size())
#define INF (0x3f3f3f3f)
#define INF1 (0x7f7f7f7f)
#define debug(...) fprintf(stderr, __VA_ARGS__)

template <typename T> inline bool chkmax(T &a, T b) { return a < b ? a = b, 1 : 0; }
template <typename T> inline bool chkmin(T &a, T b) { return b < a ? a = b, 1 : 0; }

//template <typename T> inline T read() {
//	register T _ = 0, __ = 1; char c_ = getchar();
//	for ( ; c_ < '0' || c_ > '9'; c_ = getchar()) if (c_ == '-') __ = -1;
//	for ( ; c_ >= '0' && c_ <= '9'; c_ = getchar()) _ = (_ << 1) + (_ << 3) + (c_ ^ 48);
//	return _ * __;
//}

const int MAXN = 1e5 + 5, MAXM = 2e5 + 5;

int n, m, e, beg[MAXN], nex[MAXM], v[MAXM], dep[MAXN], fa[18][MAXN], c[MAXN], vis[MAXN], rt;
LL fw[MAXN];
PII E[MAXN];

void add(int uu, int vv) {
	v[++ e] = vv, nex[e] = beg[uu], beg[uu] = e;
}

void DFS(int u, int pa) {
	vis[u] = 1, fa[0][u] = pa, dep[u] = dep[pa] + 1, fw[u] = c[u];
	for (int i = beg[u]; i; i = nex[i])
		if (!vis[v[i]]) DFS(v[i], u), fw[u] -= fw[v[i]];
}

int LCA(int u, int v) {
	if (dep[u] < dep[v]) swap(u, v);
	int d = dep[u] - dep[v];
	For(i, 0, 16) if (d & (1 << i)) u = fa[i][u];
	if (u == v) return u;
	Fordown(i, 16, 0) if (fa[i][u] != fa[i][v])
		u = fa[i][u], v = fa[i][v];
	return fa[0][u];
}

int main() {
#ifdef hany01
	freopen("e.in", "r", stdin);
	freopen("e.out", "w", stdout);
#endif

	srand(19260817);

	scanf("%d%d", &n, &m);
	For(i, 1, n) scanf("%d", c + i);
	For(i, 1, m) {
		scanf("%d%d", &E[i].X, &E[i].Y);
		add(E[i].X, E[i].Y), add(E[i].Y, E[i].X);
	}

	rt = rand() % n + 1;

	DFS(rt, rt);
	if (fw[rt] % 2) {
		puts("NO");
		return 0;
	}
	if (!fw[rt]) {
		puts("YES");
		For(i, 1, m) {
			if (fa[0][E[i].X] == E[i].Y) swap(E[i].X, E[i].Y);
			if (fa[0][E[i].Y] == E[i].X) printf("%lld\n", fw[E[i].Y]);
			else puts("0");
		}
		return 0;
	}

	For(i, 1, 16) For(u, 1, n)
		fa[i][u] = fa[i - 1][fa[i - 1][u]];

	int key = 0;
	LL ans;
	For(i, 1, m) {
		if (fa[0][E[i].X] == E[i].Y) swap(E[i].X, E[i].Y);
		if (fa[0][E[i].Y] == E[i].X) continue;
		if ((dep[E[i].X] + dep[E[i].Y]) % 2) continue;
		int lca = LCA(E[i].X, E[i].Y);
		if (lca != rt) continue;
		key = i;
		if ((dep[E[i].X] - dep[lca]) % 2 == 0) ans = fw[rt] / 2;
		else ans = -fw[rt] / 2;
		LL t = -ans;
		int u = E[i].X;
		while (u != lca) fw[u] += t, t *= -1, u = fa[0][u];
		t = -ans, u = E[i].Y;
		while (u != lca) fw[u] += t, t *= -1, u = fa[0][u];
	}

	if (!key) {
		puts("NO");
		return 0;
	}

	puts("YES");
	For(i, 1, m) {
		if (fa[0][E[i].X] == E[i].Y) swap(E[i].X, E[i].Y);
		if (fa[0][E[i].Y] == E[i].X) printf("%lld\n", fw[E[i].Y]);
		else if (key == i) printf("%lld\n", ans);
		else puts("0");
	}

	return 0;
}

			 		     	 	 		   		   		 	 	