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>
using namespace std;
const int N = 100100;
using ll = long long;
struct Edge {
  int v;
  ll w;
  int nxt;
} e[N << 1];
int head[N], cnt = 1;
inline void addedge(int u, int v) {
  e[++cnt] = (Edge){v, 0, head[u]}, head[u] = cnt;
}
int n, m, vis[N], dep[N], fa[N], id[N], ind;
ll c[N];
void dfs(int x, int f) {
  vis[x] = 1, fa[x] = f, dep[x] = !dep[f];
  for (int i = head[x]; i; i = e[i].nxt)
    if (e[i].v != f) {
      if (vis[e[i].v]) {
        e[i].w = e[i ^ 1].w = 1;
        if (dep[x] == dep[e[i].v]) ind = i;
      } else {
        id[e[i].v] = i;
        dfs(e[i].v, x);
        e[i].w = e[i ^ 1].w = c[e[i].v];
        c[e[i].v] = 0;
      }
      c[x] -= e[i].w;
    }
}
int main() {
  scanf("%d %d", &n, &m);
  for (int i = 1; i <= n; i++) scanf("%lld", c + i);
  for (int i = 1, a, b; i <= m; i++)
    scanf("%d %d", &a, &b), addedge(a, b), addedge(b, a);
  dfs(1, 0);
  if (c[1] && !ind) {
    puts("NO");
    return 0;
  }
  puts("YES");
  if (c[1]) {
    int u = e[ind].v, v = e[ind ^ 1].v;
    ll x = c[1] / 2;
    for (int i = v; i != 1; i = fa[i]) {
      if (dep[i] == dep[1])
        e[id[i]].w -= x, e[id[i] ^ 1].w -= x;
      else
        e[id[i]].w += x, e[id[i] ^ 1].w += x;
    }
    for (int i = u; i != 1; i = fa[i]) {
      if (dep[i] == dep[1])
        e[id[i]].w -= x, e[id[i] ^ 1].w -= x;
      else
        e[id[i]].w += x, e[id[i] ^ 1].w += x;
    }
    if (dep[v] == dep[1])
      e[ind].w += x, e[ind ^ 1].w += x;
    else
      e[ind].w -= x, e[ind ^ 1].w -= x;
  }
  for (int i = 1; i <= m; i++) printf("%lld\n", e[i << 1].w);
}
