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, Num[101000], cnt, Dep[101000], Path[101000];
int chk[101000], ord[101000], par[101000], pL[101000];
long long R[101000], w[101000];
vector<int> E[101000], L[101000];
void DFS(int a) {
  Num[a] = ++cnt;
  ord[cnt] = a;
  int i;
  for (i = 0; i < E[a].size(); i++) {
    if (Num[E[a][i]]) continue;
    chk[L[a][i]] = 1;
    Dep[E[a][i]] = Dep[a] + 1;
    par[E[a][i]] = a;
    pL[E[a][i]] = L[a][i];
    DFS(E[a][i]);
  }
}
struct Edge {
  int a, b;
} Ed[201000];
void Pro(int a, int b, int num, long long ss) {
  int i;
  R[num] -= ss / 2;
  while (a != b) {
    if (Dep[a] < Dep[b]) swap(a, b);
    R[pL[a]] -= ss / 2;
    w[a] += ss;
    a = par[a];
  }
  w[a] += ss;
}
void Make() {
  int i;
  for (i = n; i >= 2; i--) {
    long long tt = w[ord[i]];
    R[pL[ord[i]]] += tt;
    w[par[ord[i]]] -= tt;
  }
}
int main() {
  int i, j, a, b;
  scanf("%d%d", &n, &m);
  for (i = 1; i <= n; i++) {
    scanf("%d", &w[i]);
  }
  for (i = 0; i < m; i++) {
    scanf("%d%d", &a, &b);
    E[a].push_back(b);
    E[b].push_back(a);
    L[a].push_back(i);
    L[b].push_back(i);
    Ed[i] = {a, b};
  }
  DFS(1);
  long long sum = 0;
  for (i = 1; i <= n; i++) {
    if (Dep[i] % 2 == 0)
      sum += w[i];
    else
      sum -= w[i];
  }
  if (abs(sum) % 2) {
    printf("NO\n");
    return 0;
  }
  if (sum == 0) {
    Make();
  } else {
    for (i = 0; i < m; i++) {
      if (!chk[i] && Dep[Ed[i].a] % 2 == Dep[Ed[i].b] % 2) {
        if (Dep[Ed[i].a] % 2) {
          Pro(Ed[i].a, Ed[i].b, i, sum);
          break;
        } else {
          Pro(Ed[i].a, Ed[i].b, i, -sum);
          break;
        }
      }
    }
    if (i == m) {
      printf("NO\n");
      return 0;
    }
    Make();
  }
  printf("YES\n");
  for (i = 0; i < m; i++) printf("%lld\n", R[i]);
}
