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;
int const maxn = 100003;
int n = 0, m = 0, rt = 0;
long long c[maxn], b[maxn];
struct Edge {
  int u, e;
  bool used;
  long long val;
};
Edge a[maxn];
int bc[maxn];
int find(int x) { return bc[x] == x ? x : bc[x] = find(bc[x]); }
int d[maxn];
int head[maxn], nxt[maxn << 1], to[maxn << 1], cnt = 1;
int which[maxn];
inline void insert(int u, int e, int id) {
  nxt[++cnt] = head[u];
  head[u] = cnt;
  to[cnt] = e;
  which[cnt] = id;
}
int fa[maxn], dep[maxn], siz[maxn], son[maxn], top[maxn];
int fr[maxn];
void dfs1(int x, int f, int li) {
  fa[x] = f;
  dep[x] = dep[f] + 1;
  siz[x] = 1;
  fr[x] = which[li];
  for (int i = head[x]; i; i = nxt[i])
    if (to[i] != f) {
      dfs1(to[i], x, i);
      b[x] += a[which[i]].val;
      siz[x] += siz[to[i]];
      if (siz[to[i]] > siz[son[x]]) son[x] = siz[x];
    }
  if (f) {
    a[which[li]].val = c[x] - b[x];
    b[x] = c[x];
  }
}
void dfs2(int x, int t) {
  top[x] = t;
  if (son[x]) dfs2(son[x], t);
  for (int i = head[x]; i; i = nxt[i])
    if (to[i] != son[x] && to[i] != fa[x]) dfs2(to[i], to[i]);
}
inline int LCA(int x, int y) {
  while (top[x] != top[y])
    dep[top[x]] > dep[top[y]] ? x = fa[top[x]] : y = fa[top[y]];
  return dep[x] > dep[y] ? y : x;
}
inline int dis(int x, int y) { return dep[x] + dep[y] - 2 * dep[LCA(x, y)]; }
int dPoi[maxn], dEdg[maxn];
void outAnsYes() {
  printf("YES\n");
  for (int i = 1; i <= m; ++i) printf("%lld\n", a[i].val);
}
int main() {
  scanf("%d %d", &n, &m);
  for (int i = 1; i <= n; ++i) scanf("%lld", c + i);
  for (int i = 1; i <= n; ++i) bc[i] = i;
  for (int i = 1; i <= m; ++i) {
    scanf("%d %d", &a[i].u, &a[i].e);
    if (find(a[i].u) == find(a[i].e)) {
      a[i].used = false;
      continue;
    }
    insert(a[i].u, a[i].e, i);
    insert(a[i].e, a[i].u, i);
    ++d[a[i].u];
    ++d[a[i].e];
    bc[find(a[i].u)] = find(a[i].e);
    a[i].used = true;
    printf("%d %d\n", a[i].u, a[i].e);
  }
  if (n == 2) {
    if (c[1] == c[2]) {
      puts("YES");
      printf("%lld\n", c[1]);
      for (int i = 2; i <= m; ++i) printf("0\n");
    } else
      puts("NO");
    return 0;
  }
  for (int i = 1; i <= n; ++i)
    if (d[i] > 1) {
      rt = i;
      break;
    }
  dfs1(rt, 0, 0);
  if (c[rt] == b[rt]) {
    outAnsYes();
    return 0;
  }
  if (abs(c[rt] - b[rt]) % 2) {
    printf("NO\n");
    return 0;
  }
  for (int i = 1; i <= m; ++i) {
    if (!a[i].used && dis(a[i].u, a[i].e) % 2 == 0) {
      dEdg[i] = 1;
      for (int y = a[i].u, k = 1; y; y = fa[y], k = -k) {
        dPoi[y] += k;
        dEdg[fr[y]] -= k;
      }
      for (int y = a[i].e, k = 1; y; y = fa[y], k = -k) {
        dPoi[y] += k;
        dEdg[fr[y]] -= k;
      }
      long long X = (c[rt] - b[rt]) / dPoi[rt];
      for (int j = 1; j <= m; ++j) a[j].val += dEdg[j] * X;
      outAnsYes();
      return 0;
    }
  }
  printf("NO\n");
  return 0;
}
