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

//CF901D 图论 生成树
#include<bits/stdc++.h>

#define file(s) freopen(s".in", "r", stdin), freopen(s".out", "w", stdout)
#define go(x, i) for(register int i = head[x]; i; i = nxt[i])
#define For(i, a, b) for(register int i = (a), i##_end_ = (b); i <= i##_end_; ++ i)
#define DFor(i, a, b) for(register int i = (a), i##_end_ = (b); i >= i##_end_; -- i)
#define debug(x) cout << #x << " = " << x << endl
#define mem(a, b) memset(a, b, sizeof(a))
#define cpy(a, b) memcpy(a, b, sizeof(a))
#define min(a, b) (a < b ? a : b)
#define max(a, b) (b < a ? a : b)
#define inf (0x3f3f3f3f)
#define INF (1e18)
#define pb push_back
#define mp make_pair
#define x first
#define y second
#define read() Read<int>()

typedef unsigned long long ull;
typedef unsigned int uint;
typedef long long ll;
typedef std::pair<ll, int> PLI;
typedef std::pair<int, int> PII;
typedef double db;

namespace IO {
#define getc() ((S_ == T_) && (T_ = (S_ = Ch_) + fread(Ch_, 1, Buffsize, stdin), S_ == T_) ? 0 : *S_ ++)
	const uint Buffsize = 1 << 15, Output = 1 << 23;
	static char Ch_[Buffsize], *S_ = Ch_, *T_ = Ch_;
	static char Out[Output], *nowps = Out;
	inline void flush(){fwrite(Out, 1, nowps - Out, stdout); nowps = Out;}
	template<typename T >inline T Read() {
		T _ = 0; static char __; T ___ = 1;
		for(__ = getc(); !isdigit(__); __=getc()) if(__ == '-') ___ = -1;
		for(; isdigit(__); __ = getc()) _ = (_ << 3) + (_ << 1) + (__ ^ 48);
		return _ *= ___;
	}
	template<typename T>inline void write(T _, char __ = '\n') {
		if(!_) *nowps ++ = '0';
		if(_ < 0) *nowps ++ = '-', _ = -_;
		static uint sta[111], tp;
		for(tp = 0; _; _ /= 10) sta[++ tp] = _ % 10;
		for(; tp; *nowps ++ = sta[tp --] ^ 48); 
		(*nowps ++) = __;
	}
	template<class T>inline bool chkmax(T &_, T __) {return _ < __ ? _ = __, 1 : 0;}
	template<class T>inline bool chkmin(T &_, T __) {return _ > __ ? _ = __, 1 : 0;}
}

using namespace std;
using namespace IO;

const int N = 1e5 + 10;
int n,m,su,sv;
int c[N],sz[N],fa[N][20],dep[N],Sumw[N];
struct Edge {int to,nxt,p,w,from;}E[N << 1];int beg[N],e = 1;
void add(int u,int v) {E[++e].to = v;E[e].nxt = beg[u];beg[u] = e;E[e].from = u;}

bool vis[N];
void dfs_tree(int u) {
	vis[u] = 1;
	for(int i = beg[u]; i; i = E[i].nxt) {
		int v = E[i].to ;
		if(!vis[v]) {
			E[i].p = E[i ^ 1].p = 1;
			dfs_tree(v) ;
		}
	}
}
void dfs_init(int u,int f) {
	dep[u] = dep[f] + 1;sz[u] = 1;
	fa[u][0] = f;
	for(int i = beg[u]; i; i = E[i].nxt) {
		int v = E[i].to;
		if(v == f || !E[i].p) continue ;
		dfs_init(v, u);
		sz[u] += sz[v];
	}
}
int Lca(int x,int y) {
	if(dep[x] < dep[y]) swap(x, y) ;
	DFor(i, 19, 0) {
		if(dep[fa[x][i]] > dep[y]) 
			x = fa[x][i];
	}
	su = x,sv = 0;
	x = fa[x][0];
	if(x == y) return x;
	DFor(i, 19, 0) 
		if(fa[x][i] != fa[y][i]) {
			x = fa[x][i];
			y = fa[y][i];
		}
	su = x, sv = y;
	return fa[x][0];
}
void dfs(int u,int f) {
	for(int i = beg[u];i;i = E[i].nxt) {
		int v = E[i].to;
		if(v == f || !E[i].p) continue ;
		dfs(v, u);
		E[i].w = c[v] - Sumw[v];
		Sumw[u] += E[i].w;
	}
}
int len = 0;
void dfs2(int u,int w,int step) {
	++len;
	for(int i = beg[u];i;i = E[i].nxt) {
		int v = E[i].to;
		if(dep[v] < dep[u] && E[i].p) {
			dfs2(v, w, step + 1);
			if(((step + 1) & 1) == (len & 1)) E[i].w += w;
			else E[i].w -= w;
		}
	}
}
int main() {
//	file("CF901D");
	n = read(), m = read();
	For(i, 1, n) c[i] = read();
	For(i, 1, m) {
		int x = read(), y = read();
		add(x, y), add(y, x);
	}
	dfs_tree(1);dfs_init(1, 0);
	For(i, 1, 19) 
		For(j, 1, n) 
			fa[j][i] = fa[fa[j][i - 1]][i - 1];
	dfs(1, 0);
	for(int i = beg[1];i;i = E[i].nxt) 
		c[1] -= E[i].w;
	if(c[1] & 1) return puts("NO"), 0;
	for(int i = 2;i <= e;i += 2) 
		if(!E[i].p) {
			int u = E[i].from, v = E[i].to;
			int f = Lca(u, v), siz = sz[su] + sz[sv] + 1;
			if(siz % 2) {
				int tot = c[1] / 2;
				len = 0;dfs2(u, tot, 1);
				len = 0;dfs2(v, tot, 1);
				if((len & 1) == 0) E[i].w -= tot;
				else E[i].w += tot;
				c[1] = 0;
			}
		}
	if(c[1] != 0) return puts("NO"), 0;
	puts("YES");
	for(int i = 2;i <= e;i += 2) 
		printf("%d\n",E[i].w + E[i + 1].w);
	return flush(), 0;
}
