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;
typedef struct node {
  int first, second, third;
  node() {}
  node(int a, int b, int c) { first = a, second = b, third = c; }
} triple;
vector<triple> G;
vector<int> hd, mark, path, c, _path;
vector<long long> wh;
void add(int u, int v, int w) {
  G.push_back(triple(v, hd[u], w));
  hd[u] = G.size() - 1;
}
int trav(int x, int t) {
  int i, j, tmp, k;
  path.push_back(x);
  mark[x] = t;
  for (i = hd[x]; ~i; i = G[i].second) {
    j = G[i].first;
    if (mark[j]) {
      if (mark[j] == mark[x]) {
        for (k = path.size() - 1; path[k] != j; k--)
          ;
        _path.clear();
        for (; k != path.size(); k++) _path.push_back(path[k]);
        return j;
      }
    } else {
      tmp = trav(j, 3 - t);
      if (~tmp) return tmp;
    }
  }
  path.pop_back();
  return -1;
}
void wt(int x, int e) {
  long long w;
  int i, j, k;
  mark[x] = 1;
  w = c[x];
  for (i = hd[x]; ~i; i = G[i].second) {
    j = G[i].first;
    k = G[i].third;
    if (!mark[j]) {
      wt(j, k);
      w -= wh[k];
    }
  }
  if (~e) wh[e] = w;
}
void cyc(int x, int t, long long d) {
  int i, j;
  for (i = hd[x]; ~i; i = G[i].second) {
    j = G[i].first;
    if (j != (t == _path.size() ? _path[0] : _path[t])) continue;
    wh[G[i].third] += d;
    if (t != _path.size()) cyc(j, t + 1, -d);
    return;
  }
}
int main() {
  int n, m, i, u, v, vtx;
  long long delt;
  scanf("%d%d", &n, &m);
  c.clear();
  for (i = 0; i < n; i++) {
    scanf("%d", &v);
    c.push_back(v);
  }
  hd.clear();
  hd.resize(n, -1);
  G.clear();
  for (i = 0; i < m; i++) {
    scanf("%d%d", &u, &v);
    u--, v--;
    add(u, v, i), add(v, u, i);
  }
  wh.clear();
  wh.resize(m, 0LL);
  mark.clear();
  mark.resize(n, 0);
  path.clear();
  vtx = trav(0, 1);
  mark.clear();
  mark.resize(n, 0);
  wt(~vtx ? vtx : 0, -1);
  delt = c[~vtx ? vtx : 0];
  for (i = hd[~vtx ? vtx : 0]; ~i; i = G[i].second) {
    delt -= wh[G[i].third];
  }
  if (vtx == -1 && delt != 0) {
    printf("NO\n");
    return 0;
  }
  if (~vtx) {
    cyc(vtx, 1, delt / 2);
  }
  printf("YES\n");
  for (i = 0; i < m; i++) {
    printf("%lld\n", wh[i]);
  }
  return 0;
}
