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 long long N = 100010;
struct edge {
  long long la, b;
  edge(long long la = 0, long long b = 0) : la(la), b(b){};
} con[N << 1];
long long tot = 1, fir[N];
void add(long long from, long long to) {
  con[++tot] = edge(fir[from], to);
  fir[from] = tot;
  con[++tot] = edge(fir[to], from);
  fir[to] = tot;
}
long long c[N], ans[N], n, m, cnt, dep[N], rt, ano, fat[N], up[N], mar[N];
struct data {
  long long a, b, id;
  data(long long a = 0, long long b = 0, long long id = 0)
      : a(a), b(b), id(id) {}
} ed[N];
pair<long long, long long> ext[N];
bool vis[N];
void dfs_init(long long pos, long long fa) {
  fat[pos] = fa;
  vis[pos] = 1;
  dep[pos] = dep[fa] + 1;
  for (long long i = fir[pos]; i; i = con[i].la) {
    if (con[i].b == fa) continue;
    if (vis[con[i].b]) {
      if (pos > con[i].b) ext[++cnt] = pair<long long, long long>(pos, i);
    } else
      dfs_init(con[i].b, pos), up[con[i].b] = (ed[((i) | 1) >> 1].id);
  }
}
long long dfs(long long pos, long long fa) {
  vis[pos] = 1;
  long long now = c[pos];
  for (long long i = fir[pos]; i; i = con[i].la) {
    if (vis[con[i].b]) continue;
    now -= (ans[(ed[((i) | 1) >> 1].id)] = dfs(con[i].b, pos));
  }
  return now;
}
bool ocy(pair<long long, long long> x) {
  long long a = x.first, b = con[x.second].b;
  return (dep[a] + dep[b] + 1) & 1;
}
void print() {
  puts("YES");
  for (long long i = 1; i <= m; ++i) {
    cout << ans[i] << endl;
  }
}
void modify(long long x, long long y) {
  long long k1 = 1, k2 = -1;
  while (dep[x] > dep[y]) {
    mar[up[x]] += k1;
    k1 = -k1;
    x = fat[x];
  }
  while (dep[y] > dep[x]) {
    mar[up[y]] += k2;
    k2 = -k2;
    y = fat[y];
  }
  while (x != y) {
    mar[up[x]] += k1;
    k1 = -k1;
    x = fat[x];
    mar[up[y]] += k2;
    k2 = -k2;
    y = fat[y];
  }
}
signed main() {
  long long a, b;
  cin >> n >> m;
  for (long long i = 1; i <= n; ++i) cin >> c[i];
  for (long long i = 1; i <= m; ++i) {
    cin >> a >> b;
    ed[i] = data(a, b, i);
  }
  random_shuffle(ed + 1, ed + m + 1);
  for (long long i = 1; i <= m; ++i) add(ed[i].a, ed[i].b);
  dfs_init(1, 0);
  for (long long i = 1; i <= cnt; ++i) {
    if (ocy(ext[i])) {
      rt = ext[i].first, ano = con[ext[i].second].b;
      modify(rt, ano);
      mar[(ed[((ext[i].second) | 1) >> 1].id)]++;
      break;
    }
  }
  memset(vis, 0, sizeof vis);
  if (rt) {
    long long uns = dfs(rt, 0) >> 1;
    for (long long i = 1; i <= m; ++i) ans[i] += mar[i] * uns;
    print();
  } else {
    if (dfs(1, 0) != 0)
      puts("NO");
    else
      print();
  }
  return 0;
}
