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;
void qmax(int &x, int y) {
  if (x < y) x = y;
}
void qmin(int &x, int y) {
  if (x > y) x = y;
}
inline int read() {
  char s;
  int k = 0, base = 1;
  while ((s = getchar()) != '-' && s != EOF && !(isdigit(s)))
    ;
  if (s == EOF) exit(0);
  if (s == '-') base = -1, s = getchar();
  while (isdigit(s)) k = k * 10 + (s ^ '0'), s = getchar();
  return k * base;
}
inline void write(long long x) {
  static char cnt, num[20];
  cnt = 0;
  if (!x) {
    putchar('0');
    return;
  }
  for (; x; x /= 10) num[++cnt] = x % 10;
  for (; cnt; putchar(num[cnt--] + 48))
    ;
}
const int maxn = 1e5 + 10;
int po[maxn], to[maxn << 1], ne[maxn << 1], id, ft[maxn];
int vis[maxn], v[maxn], dis[maxn], fa[maxn], Map[maxn], yz[maxn], rp[maxn];
int n, m;
long long c[maxn], a[maxn];
long long sroot;
void add(int x, int y) {
  id++;
  to[id] = y, ne[id] = po[x], po[x] = id;
}
void dfs(int x) {
  v[x] = 1;
  dis[x] = dis[fa[x]] + 1;
  for (int i = po[x]; i; i = ne[i]) {
    if (!v[to[i]]) {
      yz[x] = 1;
      fa[to[i]] = x;
      Map[to[i]] = i >> 1;
      dfs(to[i]);
      rp[x] |= (rp[to[i]] >> 1);
      vis[i >> 1] = 1;
    }
    if (v[to[i]] && to[i] != fa[x])
      if (!((dis[x] - dis[to[i]]) & 1)) {
        ft[x] = i >> 1;
        rp[x] = 2;
      }
  }
}
void dfs1(int x) {
  if (!yz[x]) {
    a[Map[x]] = c[x];
    return;
  }
  a[Map[x]] = c[x];
  for (int i = po[x]; i; i = ne[i])
    if (vis[i >> 1] && to[i] != fa[x]) {
      dfs1(to[i]);
      a[Map[x]] -= a[Map[to[i]]];
    }
  if (x == 1) sroot = a[Map[x]];
}
int main() {
  n = read();
  m = read();
  id = 1;
  for (int i = 1; i <= n; i++) c[i] = read();
  for (int i = 1, x, y; i <= m; i++) {
    x = read(), y = read();
    add(x, y);
    add(y, x);
  }
  dfs(1);
  Map[1] = 0;
  dfs1(1);
  if (sroot & 1) {
    printf("NO\n");
    return 0;
  }
  if (sroot != 0 && !rp[1]) {
    printf("NO\n");
    return 0;
  }
  if (sroot != 0) {
    int p = 1;
    while ((rp[p] & 2) != 2) {
      for (int i = po[p]; i; i = ne[i])
        if (vis[i >> 1] && to[i] != fa[p] && rp[to[i]]) {
          a[Map[to[i]]] += sroot;
          sroot = -sroot;
          p = to[i];
          break;
        }
    }
    int x = p, y = to[ft[p] * 2] + to[ft[p] * 2 + 1] - x;
    a[ft[p]] = sroot / 2;
    int z = -1;
    if (dis[y] > dis[x]) swap(x, y);
    while (x != y) {
      a[Map[x]] += z * (sroot / 2);
      z = -z;
      x = fa[x];
    }
  }
  printf("YES\n");
  for (int i = 1; i <= m; i++) printf("%lld\n", a[i]);
  return 0;
}
