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 + 7;
const int LogN = 18;
template <typename T>
inline T read() {
  T res = 0, flag = 1;
  char in = getchar();
  while (!isdigit(in)) {
    if (in == '-') flag = -1;
    in = getchar();
  }
  while (isdigit(in)) {
    res = (res << 1) + (res << 3) + in - '0';
    in = getchar();
  }
  return res * flag;
}
template <typename T>
inline void chkmax(T &a, T b) {
  if (a < b) a = b;
}
template <typename T>
inline void chkmin(T &a, T b) {
  if (a > b) a = b;
}
namespace DSU {
int f[MAXN];
inline void init() {
  for (int i = 1; i < MAXN; ++i) f[i] = i;
}
inline int find(int first) {
  if (f[first] == first) return first;
  return f[first] = find(f[first]);
}
inline bool inter(int first, int second) { return find(first) == find(second); }
inline void merge(int first, int second) {
  first = find(first);
  second = find(second);
  f[first] = second;
}
}  // namespace DSU
int n, m;
int C[MAXN], dep[MAXN], fa[MAXN];
int f[LogN][MAXN];
pair<int, int> edge[MAXN];
int dex, head[MAXN], nxt[MAXN], to[MAXN], w[MAXN];
bool vis[MAXN];
long long val[MAXN], Req;
inline void Link(int first, int second, int val) {
  nxt[++dex] = head[first];
  to[dex] = second;
  w[dex] = val;
  head[first] = dex;
}
inline long long dfs(int u, int Fa) {
  for (int i = 1; i < LogN; ++i) f[i][u] = f[i - 1][f[i - 1][u]];
  dep[u] = dep[Fa] + 1;
  long long res = C[u];
  for (int i = head[u]; i; i = nxt[i]) {
    int v = to[i];
    if (v == Fa) continue;
    f[0][v] = u;
    fa[v] = w[i];
    val[w[i]] = dfs(v, u);
    res -= val[w[i]];
  }
  return res;
}
inline int check(int first, int second) {
  int res = dep[first] + dep[second];
  int sx = first, sy = second;
  int A;
  if (dep[first] < dep[second]) swap(first, second);
  for (int i = LogN - 1; i >= 0; --i)
    if (dep[f[i][first]] >= dep[second]) first = f[i][first];
  if (first == second)
    A = first;
  else {
    for (int i = LogN - 1; i >= 0; --i)
      if (f[i][first] != f[i][second]) {
        first = f[i][first];
        second = f[i][second];
      }
    A = f[0][first];
  }
  res = res - dep[A] - dep[f[0][A]];
  if (!(res & 1)) return 0;
  return (dep[sx] & 1) ? 1 : -1;
}
inline void Adapt(int first, int second, int Val) {
  int sav = Val;
  while (first) {
    val[fa[first]] += sav;
    sav = -sav;
    first = f[0][first];
  }
  sav = Val;
  while (second) {
    val[fa[second]] += sav;
    sav = -sav;
    second = f[0][second];
  }
}
inline void init() {
  n = read<int>();
  m = read<int>();
  DSU::init();
  for (int i = 1; i <= n; ++i) C[i] = read<int>();
  for (int i = 1; i <= m; ++i) {
    edge[i].first = read<int>();
    edge[i].second = read<int>();
  }
  for (int i = 1; i <= m; ++i) {
    if (!DSU::inter(edge[i].first, edge[i].second)) {
      DSU::merge(edge[i].first, edge[i].second);
      Link(edge[i].first, edge[i].second, i);
      Link(edge[i].second, edge[i].first, i);
      vis[i] = true;
    }
  }
  Req = dfs(1, 0);
}
inline void solve() {
  if (!Req) {
    printf("YES\n");
    for (int i = 1; i <= m; ++i) printf("%lld\n", val[i]);
    return;
  }
  if (abs(Req) & 1) printf("NO"), exit(0);
  long long tmp;
  for (int i = 1; i <= m; ++i) {
    if (!vis[i]) {
      if (tmp = check(edge[i].first, edge[i].second)) {
        printf("YES\n");
        tmp = tmp * Req / 2;
        val[i] = tmp;
        Adapt(edge[i].first, edge[i].second, -tmp);
        for (int j = 1; j <= m; ++j) {
          printf("%lld\n", val[j]);
        }
        return;
      }
    }
  }
  printf("NO");
}
int main() {
  init();
  solve();
  return 0;
}
