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>
inline int getint() {
  char c = getchar();
  int x = 0, f = 1;
  for (; !isdigit(c); c = getchar())
    if (c == '-') f = -1;
  for (; isdigit(c); c = getchar()) x = x * 10 + c - 48;
  return x * f;
}
inline void putl(long long x) {
  if (x < 0) putchar('-'), x = -x;
  if (x) {
    static int buf[30], xb;
    for (xb = 0; x; x /= 10) buf[++xb] = x % 10;
    for (; xb;) putchar(buf[xb--] | 48);
  } else
    putchar('0');
}
const int N = 100005;
struct edge {
  int to, next;
} e[N << 1];
long long ans[N], c[N], cc[N], v;
int n, m, x, y, h[N], xb, i, dep[N], be, en, dad[N], ef[N], id;
void dfs(int x, int fa) {
  dep[x] = dep[fa] + 1;
  for (int i = h[x]; i; i = e[i].next)
    if (e[i].to != fa) {
      if (!dep[e[i].to]) {
        dfs(e[i].to, x);
        c[x] -= ans[i >> 1] = c[e[i].to];
      } else if (!((dep[e[i].to] ^ dep[x]) & 1))
        be = x;
    }
}
void dfs2(int x, int fa) {
  dep[x] = dep[dad[x] = fa] + 1;
  for (int i = h[x]; i; i = e[i].next)
    if (e[i].to != fa) {
      if (!dep[e[i].to]) {
        dfs2(e[i].to, x);
        c[x] -= ans[ef[e[i].to] = i >> 1] = c[e[i].to];
      } else if (!((dep[e[i].to] ^ dep[x]) & 1) && e[i].to == be)
        en = x, id = i >> 1;
    }
}
int main() {
  n = getint(), m = getint();
  xb = 1;
  for (i = 1; i <= n; ++i) cc[i] = c[i] = getint();
  for (i = 1; i <= m; ++i) {
    x = getint(), y = getint();
    e[++xb] = (edge){y, h[x]};
    h[x] = xb;
    e[++xb] = (edge){x, h[y]};
    h[y] = xb;
  }
  dfs(1, 0);
  if (!c[1]) {
    puts("YES");
    for (i = 1; i <= m; ++i) putl(ans[i]), putchar('\n');
    return 0;
  }
  if (be) {
    memset(dep + 1, 0, n << 2);
    memset(ans + 1, 0, m << 3);
    memcpy(c + 1, cc + 1, n << 3);
    dfs2(be, 0);
    for (ans[id] += v = c[be] >> 1, i = en, y = -1; i != be; i = dad[i], v = -v)
      ans[ef[i]] -= v;
    for (i = 1; i <= m; ++i) putl(ans[i]), putchar('\n');
  } else
    puts("NO");
  return 0;
}
