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>
#define il inline
#define RG register
#define ll long long
#define N (100005)

using namespace std;

struct edge{ int nt,to; }g[N<<1];

int head[N],vis[N],col[N],fa[N],c[N],p[N],q[N],rt,ed,n,m,num;
ll ans[N];

il int gi(){
  RG int x=0,q=1; RG char ch=getchar();
  while ((ch<'0' || ch>'9') && ch!='-') ch=getchar();
  if (ch=='-') q=-1,ch=getchar();
  while (ch>='0' && ch<='9') x=x*10+ch-48,ch=getchar();
  return q*x;
}

il void insert(RG int from,RG int to){
  g[++num]=(edge){head[from],to},head[from]=num; return;
}

il void dfs1(RG int x,RG int f){
  fa[x]=f,vis[x]=1; RG int v;
  for (RG int i=head[x];i;i=g[i].nt){
    v=g[i].to; if (v==f) continue;
    if (!vis[v]) col[v]=col[x]^1,p[v]=i,dfs1(v,x);
    else if (col[v]==col[x] && !rt) rt=v;
  }
  return;
}

il void dfs2(RG int x,RG int f){
  vis[x]=1; RG int v;
  for (RG int i=head[x];i;i=g[i].nt){
    v=g[i].to; if (v==f) continue;
    if (!vis[v]) dfs2(v,x),c[x]-=(ans[i>>1]=c[v]),c[v]=0;
  }
  return;
}

int main(){
#ifndef ONLINE_JUDGE
  freopen("tree.in","r",stdin);
  freopen("tree.out","w",stdout);
#endif
  n=gi(),m=gi(),num=1;
  for (RG int i=1;i<=n;++i) c[i]=gi();
  for (RG int i=1,u,v;i<=m;++i)
    u=gi(),v=gi(),insert(u,v),insert(v,u);
  dfs1(1,0),memset(vis,0,sizeof(vis));
  if (!rt) rt=1,ed=1; dfs2(rt,0);
  if (c[rt]){
    if (ed) puts("NO"),exit(0);
    for (RG int i=head[rt],v=g[i].to;i;i=g[i].nt,v=g[i].to)
      if (col[v]==col[rt]){ ed=v,ans[i>>1]+=c[rt]>>1; break; }
    for (RG int i=ed,fg=-1;i!=rt;i=fa[i],fg=-fg) ans[p[i]>>1]+=fg*c[rt]>>1;
  }
  puts("YES");
  for (RG int i=1;i<=m;++i) printf("%I64d\n",ans[i]);
  return 0;
}
