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 int maxn = 1e5 + 999;
struct edge {
  int to, nxt, from, ban, ji;
  long long dis;
} e[maxn << 1];
int n, c[maxn], head[maxn], tot = -1;
void add(int x, int y) {
  e[++tot].to = y;
  e[tot].from = x;
  e[tot].nxt = head[x];
  head[x] = tot;
}
int vis[maxn], stac[maxn], top, a[maxn], fl, m, dep[maxn], f[maxn];
long long delta;
namespace DSU {
int fa[maxn];
int find(int x) { return fa[x] == x ? x : fa[x] = find(fa[x]); }
}  // namespace DSU
using namespace DSU;
long long dp(int x, int fa) {
  int leaf = 1;
  long long sum = 0;
  dep[x] = dep[fa] + 1;
  f[x] = fa;
  for (int i = head[x]; ~i; i = e[i].nxt) {
    int y = e[i].to;
    if (e[i].ban || y == fa) continue;
    leaf = 0;
    e[i].dis = dp(y, x);
    sum += e[i].dis;
  }
  if (leaf) return c[x];
  return c[x] - sum;
}
void solve(int x, int fa) {
  vis[x] = 1;
  int fl = 0;
  for (int i = head[x]; ~i; i = e[i].nxt) {
    int y = e[i].to;
    if (a[y] && y != fa) {
      e[i].ji = e[i ^ 1].ji = 1;
      if (!vis[y]) solve(y, x), fl = 1;
      if (fl) return;
    }
  }
}
int main() {
  scanf("%d%d", &n, &m);
  memset(head, -1, sizeof(head));
  for (int i = 1; i <= n; ++i) scanf("%I64d", &c[i]), fa[i] = i;
  for (int i = 1; i <= m; ++i) {
    int x, y;
    scanf("%d%d", &x, &y);
    add(x, y);
    add(y, x);
  }
  for (int i = 0; i <= tot; i += 2) {
    int x = find(e[i].from), y = find(e[i].to);
    if (x == y)
      e[i].ban = e[i ^ 1].ban = 1;
    else
      fa[x] = y;
  }
  delta = dp(1, 0);
  if (delta & 1) {
    cout << "NO";
    return 0;
  } else if (delta) {
    int x, y, opt;
    for (int i = 0; i <= tot; i += 2)
      if (e[i].ban) {
        x = e[i].to, y = e[i].from;
        if ((dep[x] & 1) == (dep[y] & 1)) {
          opt = (dep[x] - dep[1]) & 1 ? -1 : 1;
          e[i].dis += opt * delta / 2;
          fl = 1;
          break;
        }
      }
    if (!fl) {
      cout << "NO";
      return 0;
    }
    delta /= 2;
    c[x] -= opt * delta;
    c[y] -= opt * delta;
    delta = dp(1, 0);
  }
  printf("YES\n");
  for (int i = 0; i <= tot; i += 2) printf("%I64d\n", e[i].dis + e[i ^ 1].dis);
  return 0;
}
