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 ex[100005], ey[100005];
vector<int> g[100005];
int n, m, c[100005];
long long a[100005], r[100005], s[2];
vector<int> g2[100005];
void dfs0(int x) {
  s[c[x]] += a[x];
  for (int i : g[x]) {
    int y = ex[i] ^ ey[i] ^ x;
    if (c[y] < 0) {
      c[y] = 1 - c[x];
      g2[x].push_back(i);
      g2[y].push_back(i);
      dfs0(y);
    }
  }
}
void dfs1(int x, int f) {
  for (int i : g2[x]) {
    int y = ex[i] ^ ey[i] ^ x;
    if (y == f) continue;
    dfs1(y, x);
    r[i] = a[y];
    a[x] -= r[i];
  }
}
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 0, ThxDem = n; i < ThxDem; ++i) scanf("%lld", a + i);
  for (int i = 0, ThxDem = m; i < ThxDem; ++i) {
    scanf("%d%d", ex + i, ey + i);
    ex[i]--;
    ey[i]--;
    g[ex[i]].push_back(i);
    g[ey[i]].push_back(i);
  }
  memset(c, -1, sizeof(c));
  c[0] = 0;
  dfs0(0);
  assert(s[0] % 2 == s[1] % 2);
  for (int i = 0, ThxDem = m; i < ThxDem; ++i)
    if (c[ex[i]] == c[ey[i]]) {
      r[i] = (s[c[ex[i]]] - s[c[ex[i] ^ 1]]) / 2;
      a[ex[i]] -= r[i];
      a[ey[i]] -= r[i];
      s[c[ex[i]]] -= 2 * r[i];
      break;
    }
  if (s[0] != s[1]) {
    puts("NO");
    return 0;
  }
  dfs1(0, -1);
  puts("YES");
  for (int i = 0, ThxDem = m; i < ThxDem; ++i) printf("%lld\n", r[i]);
  return 0;
}
