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;
template <typename T>
void read(T &x) {
  x = 0;
  bool f = 0;
  char c = getchar();
  for (; !isdigit(c); c = getchar())
    if (c == '-') f = 1;
  for (; isdigit(c); c = getchar()) x = x * 10 + (c ^ 48);
  if (f) x = -x;
}
template <typename F>
inline void write(F x, char ed = '\n') {
  static short st[30];
  short tp = 0;
  if (x < 0) putchar('-'), x = -x;
  do st[++tp] = x % 10, x /= 10;
  while (x);
  while (tp) putchar('0' | st[tp--]);
  putchar(ed);
}
template <typename T>
inline void Mx(T &x, T y) {
  x < y && (x = y);
}
template <typename T>
inline void Mn(T &x, T y) {
  x > y && (x = y);
}
const int N = 205000;
long long c[N], val[N], res[N];
int h[N], ne[N << 1], to[N << 1], tot = 1, m, n;
inline void add(int x, int y) { ne[++tot] = h[x], to[h[x] = tot] = y; }
int dep[N], son[N], f[N], siz[N], Top[N], vis[N];
void dfs1(int x, int fa) {
  dep[x] = dep[f[x] = fa] + (siz[x] = vis[x] = 1), res[x] = c[x];
  for (int i = h[x]; i; i = ne[i]) {
    int y = to[i];
    if (vis[y]) continue;
    dfs1(y, x), siz[x] += siz[y];
    if (siz[son[x]] < siz[y]) son[x] = y;
    val[i >> 1] = res[y], res[x] -= res[y];
  }
}
void dfs2(int x, int topf) {
  Top[x] = topf, vis[x] = 1, son[x] && (dfs2(son[x], topf), 0);
  for (int i = h[x], y; i; i = ne[i]) !vis[y = to[i]] && (dfs2(y, y), 0);
}
int Lca(int x, int y) {
  while (Top[x] != Top[y]) {
    if (dep[Top[x]] < dep[Top[y]]) swap(x, y);
    x = f[Top[x]];
  }
  return dep[x] < dep[y] ? x : y;
}
inline void nope(void) {
  puts("NO");
  exit(0);
}
inline void ojbk(void) {
  puts("YES");
  for (int i = 1; i <= m; i++) write(val[i]);
  exit(0);
}
int main() {
  read(n), read(m);
  for (int i = 1; i <= n; i++) read(c[i]);
  for (int i = 1, x, y; i <= m; i++) read(x), read(y), add(x, y), add(y, x);
  dfs1(1, 0), memset(vis, 0, sizeof(vis)), dfs2(1, 1);
  (res[1] & 1) ? nope(), 0 : !res[1] && (ojbk(), 0);
  for (int i = 1; i <= m; i++) {
    int x = to[i * 2], y = to[(i * 2) ^ 1];
    if ((dep[x] + dep[y]) & 1) continue;
    int t = (dep[x] & 1) ? 2 : -2, tmp = res[1] / t;
    val[i] = tmp, memset(vis, 0, sizeof(vis));
    c[x] -= tmp, c[y] -= tmp, dfs1(1, 0), ojbk();
  }
  nope();
  return 0;
}
