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;
inline int read(int f = 1, int x = 0, char ch = ' ') {
  while (!isdigit(ch = getchar()))
    if (ch == '-') f = -1;
  while (isdigit(ch)) x = x * 10 + ch - '0', ch = getchar();
  return f * x;
}
const int N = 1e5 + 5;
struct Edge {
  int next, to;
  long long w;
  Edge(int next = 0, int to = 0, long long w = 0) : next(next), to(to), w(w){};
} edge[N << 1];
int tot = 1, head[N];
void _add(int x, int y) { edge[++tot] = Edge(head[x], y), head[x] = tot; }
void add(int x, int y) { _add(x, y), _add(y, x); }
int n, m, f[N], g[N], d[N], vis[N], e[N], t;
long long c[N], w[N];
int dfs(int x, int fi) {
  vis[x] = 1, f[x] = fi;
  for (int i = head[x]; i; i = edge[i].next)
    if (i != fi) {
      int y = edge[i].to;
      if (vis[y] && ((d[y] ^ d[x] ^ 1) & 1))
        g[x] = i;
      else if (!vis[y])
        vis[y] = 1, d[y] = d[x] + 1, c[x] -= dfs(y, i ^ 1);
    }
  return edge[fi].w = edge[fi ^ 1].w = c[x];
}
void print() {
  puts("YES");
  for (int i = 1; i <= m; ++i) printf("%I64d\n", edge[i << 1].w);
}
int main() {
  n = read(), m = read();
  for (int i = 1; i <= n; ++i) c[i] = read();
  for (int i = 1; i <= m; ++i) {
    int x = read(), y = read();
    add(x, y);
  }
  d[1] = 1, dfs(1, 0);
  if (c[1] == 0) return print(), 0;
  if (~c[1] & 1)
    for (int o = 2; o <= n; ++o)
      if (g[o]) {
        if (d[o] & 1)
          edge[g[o]].w = edge[g[o] ^ 1].w += c[1] >> 1;
        else
          edge[g[o]].w = edge[g[o] ^ 1].w -= c[1] >> 1;
        for (int i = f[edge[g[o]].to], j = d[edge[g[o]].to] - 1; j;
             i = f[edge[i].to], --j)
          if (j & 1)
            edge[i].w = edge[i ^ 1].w += c[1] >> 1;
          else
            edge[i].w = edge[i ^ 1].w -= c[1] >> 1;
        for (int i = f[o], j = d[o] - 1; j; i = f[edge[i].to], --j)
          if (j & 1)
            edge[i].w = edge[i ^ 1].w += c[1] >> 1;
          else
            edge[i].w = edge[i ^ 1].w -= c[1] >> 1;
        return print(), 0;
      }
  if (g[1]) {
    for (int i = f[edge[g[1]].to]; i; i = f[edge[i].to]) e[++t] = i;
    e[++t] = g[1];
    for (int i = 1; i <= t; ++i) w[i] = edge[e[i]].w + edge[e[i - 1]].w;
    w[1] -= edge[0].w, w[t] += edge[0].w;
    for (int i = 1; i <= t; ++i)
      edge[g[1] ^ 1].w = edge[g[1]].w += i & 1 ? w[i] : -w[i];
    if (edge[g[1]].w & 1) return puts("NO"), 0;
    edge[g[1] ^ 1].w = edge[g[1]].w >>= 1;
    for (int i = 1, j = edge[g[1]].w; i < t; ++i)
      j = edge[e[i] ^ 1].w = edge[e[i]].w = w[i] - j;
    return print(), 0;
  }
  puts("NO");
  return 0;
}
