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 = 1e5 + 10, K = 20;
long long W[N], tmp[N], w[N];
struct edge {
  int x, y;
} a[N];
int to[N << 1], fs[N], nx[N << 1], e = 1;
int fr[N];
int vis[N], c[N];
int dep[N], fa[N][K];
inline void add(int x, int y) {
  to[++e] = y;
  nx[e] = fs[x];
  fs[x] = e;
}
void dfs(int x, int f) {
  dep[x] = dep[f] + 1;
  fa[x][0] = f;
  for (int i = 1; i <= 16; ++i) fa[x][i] = fa[fa[x][i - 1]][i - 1];
  for (int i = fs[x]; i; i = nx[i]) {
    int k = to[i];
    if (k == f || vis[k]) continue;
    fr[k] = i >> 1;
    vis[k] = c[i >> 1] = 1;
    dfs(k, x);
    w[i >> 1] = W[k];
    W[x] -= w[i >> 1], W[k] -= w[i >> 1];
  }
}
inline int lca(int x, int y) {
  if (dep[x] < dep[y]) swap(x, y);
  for (int i = 16; ~i; --i)
    if (dep[fa[x][i]] >= dep[y]) x = fa[x][i];
  if (x == y) return x;
  for (int i = 16; ~i; --i)
    if (fa[x][i] ^ fa[y][i]) x = fa[x][i], y = fa[y][i];
  return fa[x][0];
}
inline void climb(int x, int t, int val) {
  for (int tp = -1; x ^ t; x = fa[x][0], tp = -tp) w[fr[x]] += tp * val;
}
int main() {
  int n, m;
  scanf("%d%d", &n, &m);
  for (int x = 1; x <= n; ++x) scanf("%lld", &W[x]), tmp[x] = W[x];
  for (int i = 1; i <= m; ++i) {
    int x, y;
    scanf("%d%d", &x, &y);
    a[i] = (edge){x, y};
    add(x, y), add(y, x);
  }
  vis[1] = 1, dfs(1, 0);
  if (!W[1]) {
    puts("YES");
    for (int x = 1; x <= m; ++x) printf("%lld\n", w[x]);
    return 0;
  }
  if (W[1] & 1) return puts("NO"), 0;
  for (int i = 1; i <= m; ++i) {
    if (c[i]) continue;
    int x = a[i].x, y = a[i].y;
    int t = lca(x, y);
    if ((dep[x] + dep[y] - dep[t] - dep[fa[t][0]]) & 1) {
      int val = W[1] / 2;
      tmp[x] -= val, tmp[y] -= val;
      for (int k = 1; k <= n; ++k) W[k] = tmp[k];
      memset(w, 0, sizeof w);
      memset(vis, 0, sizeof vis);
      vis[1] = 1, dfs(1, 0);
      if (!W[1]) {
        puts("YES");
        w[i] += val;
        for (int k = 1; k <= m; ++k) printf("%lld\n", w[k]);
        return 0;
      }
      tmp[x] += val * 2, tmp[y] += val * 2;
      for (int k = 1; k <= n; ++k) W[k] = tmp[k];
      memset(w, 0, sizeof w);
      memset(vis, 0, sizeof vis);
      vis[1] = 1, dfs(1, 0);
      puts("YES");
      w[i] -= val;
      for (int k = 1; k <= m; ++k) printf("%lld\n", w[k]);
      return 0;
    }
  }
  puts("NO");
  return 0;
}
