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;
int n, m, tot = 1, sz, e, Dep[100000 + 5], Head[100000 + 5], Fa[100000 + 5],
          Ord[100000 + 5];
long long Sum[2], A[100000 + 5], Ans[100000 + 5];
struct Edge {
  int next, node;
  long long w;
} h[100000 + 5 << 1];
void addedge(int u, int v) {
  h[++tot].next = Head[u], Head[u] = tot;
  h[tot].node = v;
}
void dfs(int z, int fa) {
  Ord[z] = z;
  Sum[Dep[z] & 1] += A[z];
  for (int i = Head[z]; i; i = h[i].next) {
    int d = h[i].node;
    if (d == fa) continue;
    if (Dep[d] && (Dep[d] + Dep[z] + 1 & 1))
      e = i >> 1;
    else if (!Dep[d]) {
      Dep[d] = Dep[z] + 1;
      Fa[d] = i;
      dfs(d, z);
    }
  }
}
bool cmp(int u, int v) { return Dep[u] < Dep[v]; }
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= n; i++) scanf("%lld", A + i);
  for (int i = 1, u, v; i <= m; i++) {
    scanf("%d%d", &u, &v);
    addedge(u, v);
    addedge(v, u);
  }
  dfs(Dep[1] = 1, 0);
  if (Sum[0] + Sum[1] & 1) {
    puts("NO");
    return 0;
  }
  if (Sum[0] != Sum[1]) {
    if (!e) {
      puts("NO");
      return 0;
    } else {
      if (Dep[h[e << 1].node] & 1) {
        Ans[e] = Sum[1] - Sum[0] >> 1;
        Sum[1] = Sum[0];
      } else {
        Ans[e] = Sum[0] - Sum[1] >> 1;
        Sum[0] = Sum[1];
      }
      A[h[e << 1].node] -= Ans[e];
      A[h[e << 1 | 1].node] -= Ans[e];
    }
  }
  sort(Ord + 1, Ord + n + 1, cmp);
  for (int i = n; i > 1; i--) {
    int z = Ord[i], t = Fa[z];
    Ans[t >> 1] = A[z];
    A[z] -= Ans[t >> 1];
    A[h[t ^ 1].node] -= Ans[t >> 1];
  }
  puts("YES");
  for (int i = 1; i <= m; i++) printf("%lld\n", Ans[i]);
  return 0;
}
