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 MAX = 112345;
struct Edge {
  int v, nxt;
} edge[MAX << 2];
int head[MAX], etot;
void add_edge(int u, int v) {
  edge[etot] = (Edge){v, head[u]};
  head[u] = etot++;
}
int dep[MAX], f[MAX], A[MAX], eid = -1, x, y;
bool vis[MAX];
long long cost[MAX], from[MAX];
long long dfs(int u, int fa) {
  vis[u] = true;
  dep[u] = dep[fa] + 1;
  f[u] = fa;
  long long sum = 0;
  for (int i = head[u]; ~i; i = edge[i].nxt) {
    int v = edge[i].v;
    if (vis[v] && dep[v] < dep[u] && (dep[u] - dep[v]) % 2 == 0) {
      eid = i;
      x = v, y = u;
    }
    if (vis[v]) continue;
    from[v] = i >> 1;
    dfs(v, u);
    sum += cost[i >> 1];
  }
  if (from[u] != -1) cost[from[u]] = A[u] - sum;
  return A[u] - sum;
}
int n, m;
void out() {
  printf("YES\n");
  for (int i = 0; i < m; i++) {
    printf("%lld\n", cost[i]);
  }
}
int main() {
  memset(from, -1, sizeof(from));
  memset(head, -1, sizeof(head));
  scanf("%d %d", &n, &m);
  for (int i = 1; i <= n; i++) scanf("%d", A + i);
  for (int i = 1; i <= m; i++) {
    int u, v;
    scanf("%d %d", &u, &v);
    add_edge(u, v);
    add_edge(v, u);
  }
  long long remain = dfs(1, 0);
  if (remain == 0) {
    out();
    return 0;
  }
  if (remain % 2 || eid == -1) {
    printf("NO\n");
    return 0;
  }
  cost[eid / 2] = remain / 2;
  ;
  if (dep[x] % 2 == 0) cost[eid / 2] *= -1;
  while (dep[y] > dep[x]) {
    cost[from[y]] += ((dep[y] - 1) % 2 ? 1 : -1) * remain / 2;
    y = f[y];
  }
  while (x > 1) {
    cost[from[x]] += ((dep[x] - 1) % 2 ? 1 : -1) * remain;
    x = f[x];
  }
  out();
}
