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, x = 0;
  char ch = getchar();
  while (ch < '0' || ch > '9') {
    if (ch == '-') f = -1;
    ch = getchar();
  }
  while (ch >= '0' && ch <= '9') {
    x = x * 10 + ch - '0';
    ch = getchar();
  }
  return x * f;
}
int stack[20];
template <typename T>
inline void write(T x) {
  if (x < 0) {
    putchar('-');
    x = -x;
  }
  if (!x) {
    putchar('0');
    return;
  }
  int top = 0;
  while (x) stack[++top] = x % 10, x /= 10;
  while (top) putchar(stack[top--] + '0');
}
template <typename T>
inline void pr1(T x) {
  write(x);
  putchar(' ');
}
template <typename T>
inline void pr2(T x) {
  write(x);
  putchar('\n');
}
const int MAXN = 100005;
struct edge {
  int x, y, next;
} a[2 * MAXN];
int len = 1, last[MAXN];
void ins(int x, int y) {
  len++;
  a[len].x = x;
  a[len].y = y;
  a[len].next = last[x];
  last[x] = len;
}
int val[MAXN], n, m, vis[MAXN], dep[MAXN], upE[MAXN];
bool tf = false;
int nowk;
long long ans[MAXN];
long long dfs(int x, int fa) {
  vis[x] = 1;
  long long sum = val[x];
  for (int k = last[x]; k; k = a[k].next) {
    int y = a[k].y;
    if (!vis[y])
      upE[y] = k, dep[y] = dep[x] + 1, sum -= (ans[k >> 1] = dfs(y, x));
    else {
      tf |= (dep[x] - dep[y] + 1) & 1;
      if ((dep[x] - dep[y] + 1) & 1) nowk = k;
    }
  }
  return sum;
}
int main() {
  n = read();
  m = read();
  for (int i = 1; i <= n; i++) val[i] = read();
  for (int i = 1; i <= m; i++) {
    int x = read(), y = read();
    ins(x, y);
    ins(y, x);
  }
  long long o = dfs(1, 0);
  if (o & 1)
    return puts("NO"), 0;
  else if (o && !tf)
    return puts("NO"), 0;
  puts("YES");
  int up = dep[a[nowk].x] < dep[a[nowk].y] ? a[nowk].x : a[nowk].y;
  int down = (a[nowk].x == up ? a[nowk].y : a[nowk].x);
  for (int u = down, op = 0; u != up; u = a[upE[u]].x, op ^= 1) {
    if (!op)
      ans[upE[u] >> 1] -= o >> 1;
    else
      ans[upE[u] >> 1] += o >> 1;
  }
  if (dep[up] & 1)
    ans[nowk >> 1] = -(o >> 1);
  else
    ans[nowk >> 1] = o >> 1;
  for (int i = 1; i <= m; i++) pr2(ans[i]);
  return 0;
}
