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;
template <class T>
void _R(T &x) {
  cin >> x;
}
void _R(int &x) { scanf("%d", &x); }
void _R(int64_t &x) { scanf("%lld", &x); }
void _R(double &x) { scanf("%lf", &x); }
void _R(char &x) { scanf(" %c", &x); }
void _R(char *x) { scanf("%s", x); }
void R() {}
template <class T, class... U>
void R(T &head, U &...tail) {
  _R(head);
  R(tail...);
}
template <class T>
void _W(const T &x) {
  cout << x;
}
void _W(const int &x) { printf("%d", x); }
void _W(const int64_t &x) { printf("%lld", x); }
void _W(const double &x) { printf("%.16f", x); }
void _W(const char &x) { putchar(x); }
void _W(const char *x) { printf("%s", x); }
template <class T, class U>
void _W(const pair<T, U> &x) {
  _W(x.first);
  putchar(' ');
  _W(x.second);
}
template <class T>
void _W(const vector<T> &x) {
  for (auto i = x.begin(); i != x.end(); _W(*i++))
    if (i != x.cbegin()) putchar(' ');
}
void W() {}
template <class T, class... U>
void W(const T &head, const U &...tail) {
  _W(head);
  putchar(sizeof...(tail) ? ' ' : '\n');
  W(tail...);
}
template <class T, class... U>
void DEBUG(const T &head, const U &...tail) {}
int MOD = 1e9 + 7;
void ADD(int64_t &x, int64_t v) {
  x = (x + v) % MOD;
  if (x < 0) x += MOD;
}
const int SIZE = 1e6 + 10;
vector<pair<int, int> > e[SIZE];
int lv[SIZE], lt[SIZE];
int64_t c[SIZE];
bool u[SIZE];
bool in_odd_cycle[SIZE];
vector<int> odd_cycle;
int64_t an[SIZE];
void dfs(int x) {
  u[x] = 1;
  for (int i = 0; i < (((int)(e[x]).size())); ++i) {
    int y = e[x][i].first;
    if (u[y]) {
      if (lv[y] < lv[x] && y != lt[x] && (lv[x] - lv[y]) % 2 == 0 &&
          !((int)(odd_cycle).size())) {
        int now = x;
        while (now != y) {
          odd_cycle.push_back(now);
          now = lt[now];
        }
        odd_cycle.push_back(y);
      }
    } else {
      lv[y] = lv[x] + 1;
      lt[y] = x;
      dfs(y);
    }
  }
}
void dfs_even(int x) {
  u[x] = 1;
  for (int i = 0; i < (((int)(e[x]).size())); ++i) {
    int y = e[x][i].first;
    if (u[y] || in_odd_cycle[y]) continue;
    dfs_even(y);
    an[e[x][i].second] = c[y];
    c[x] -= c[y];
  }
}
int main() {
  int n, m;
  R(n, m);
  for (int i = (1); i <= (n); ++i) {
    int x;
    R(x);
    c[i] = x;
  }
  for (int i = 0; i < (m); ++i) {
    int x, y;
    R(x, y);
    e[x].push_back(make_pair(y, i));
    e[y].push_back(make_pair(x, i));
  }
  dfs(1);
  if (!((int)(odd_cycle).size())) {
    memset((u), 0, sizeof((u)));
    dfs_even(1);
    if (!c[1]) {
      puts("YES");
      for (int i = 0; i < (m); ++i) W(an[i]);
    } else
      puts("NO");
  } else {
    for (int i = 0; i < (((int)(odd_cycle).size())); ++i) {
      in_odd_cycle[odd_cycle[i]] = 1;
    }
    memset((u), 0, sizeof((u)));
    for (int i = 0; i < (((int)(odd_cycle).size())); ++i) {
      dfs_even(odd_cycle[i]);
    }
    int64_t v = 0;
    for (int i = 0; i < (((int)(odd_cycle).size())); ++i) {
      if (!i || i % 2 == 1)
        v += c[odd_cycle[i]];
      else
        v -= c[odd_cycle[i]];
    }
    if (v % 2 != 0) {
      puts("NO");
      return 0;
    }
    v /= 2;
    odd_cycle.push_back(odd_cycle[0]);
    for (int i = (1); i < (((int)(odd_cycle).size())); ++i) {
      int x = odd_cycle[i - 1];
      int y = odd_cycle[i];
      int eid = -1;
      for (int j = 0; j < (((int)(e[x]).size())); ++j) {
        if (e[x][j].first == y) {
          eid = e[x][j].second;
          break;
        }
      }
      an[eid] = v;
      v = c[y] - v;
    }
    puts("YES");
    for (int i = 0; i < (m); ++i) W(an[i]);
  }
  return 0;
}
