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 = 110000;
int head[N], np[N << 1], p[N << 1], id[N << 1], tot;
int n, m;
int c[N];
int dep[N], fa[N], vis[N];
bool is = 0;
int gtx, gty, gt;
int k[N];
long long b[N];
int a1[N];
long long a2[N];
void dd2(int x) {
  vis[x] = 1;
  for (int u = head[x]; u; u = np[u])
    if (p[u] ^ fa[x])
      if (!vis[p[u]])
        if (id[u] != gt) {
          fa[p[u]] = x;
          dd2(p[u]);
          int nk = -k[p[u]];
          long long nb = c[p[u]] - b[p[u]];
          a1[id[u]] = nk;
          a2[id[u]] = nb;
          b[x] += nb;
          k[x] += nk;
        }
}
long long ans[N];
long long hav[N];
void dd(int x) {
  for (int u = head[x]; u; u = np[u])
    if (fa[p[u]] == x) {
      dd(p[u]);
      ans[id[u]] = c[p[u]] - hav[p[u]];
      hav[x] += ans[id[u]];
    }
}
void dfs(int x) {
  vis[x] = 1;
  for (int u = head[x]; u; u = np[u])
    if (p[u] ^ fa[x]) {
      if (vis[p[u]]) {
        if (dep[p[u]] == dep[x]) {
          is = 1;
          gt = id[u];
          gtx = x;
          gty = p[u];
        }
      } else {
        fa[p[u]] = x;
        dep[p[u]] = (dep[x] ^ 1);
        dfs(p[u]);
      }
    }
}
int main() {
  scanf("%d%d", &n, &m);
  for (int i = (int)1; i <= (int)n; i++) scanf("%d", &c[i]);
  for (int i = (int)1; i <= (int)m; i++) {
    int a, b;
    scanf("%d%d", &a, &b);
    ++tot;
    p[tot] = b;
    np[tot] = head[a];
    head[a] = tot;
    id[tot] = i;
    ++tot;
    p[tot] = a;
    np[tot] = head[b];
    head[b] = tot;
    id[tot] = i;
  }
  dfs(1);
  if (!is) {
    long long s = 0;
    for (int i = (int)1; i <= (int)n; i++)
      if (dep[i])
        s += c[i];
      else
        s -= c[i];
    if (s != 0) {
      puts("NO");
      return 0;
    }
    dd(1);
    if (hav[1] != c[1]) {
      puts("NO");
      return 0;
    }
    puts("YES");
    for (int i = (int)1; i <= (int)m; i++) printf("%lld\n", ans[i]);
  } else {
    memset(fa, 0, sizeof fa);
    memset(vis, 0, sizeof vis);
    k[gty] = 1;
    a1[gt] = 1;
    printf("%d %d %d\n", gt, gtx, gty);
    dd2(gtx);
    long long x = 0;
    x = (c[gtx] - b[gtx]) / 2;
    puts("YES");
    for (int i = (int)1; i <= (int)m; i++) printf("%lld\n", x * a1[i] + a2[i]);
  }
  return 0;
}
