1 #include <cstdio>
2 #include <cstring>
3 #define min(a,b) ((a)<(b)?(a):(b))
4 #define oo 0x3f3f3f3f
5 #define N 210
6 #define M 100010
7
8 struct Dinic {
9 int n, src, dst;
10 int head[N], dest[M], flow[M], eid[M], next[M], etot;
11 int cur[N], dep[N], qu[N], bg, ed;
12
13 void init( int n, int src, int dst ) {
14 this->n = n;
15 this->src = src;
16 this->dst = dst;
17 etot = 0;
18 memset( head, -1, sizeof(head) );
19 }
20 void adde( int id, int u, int v, int f ) {
21 next[etot]=head[u], flow[etot]=f, dest[etot]=v, eid[etot]=id; head[u]=etot++;
22 next[etot]=head[v], flow[etot]=0, dest[etot]=u, eid[etot]=-1; head[v]=etot++;
23 }
24 bool bfs() {
25 memset( dep, 0, sizeof(dep) );
26 qu[bg=ed=1] = src;
27 dep[src] = 1;
28 while( bg<=ed ) {
29 int u=qu[bg++];
30 for( int t=head[u]; ~t; t=next[t] ) {
31 int v=dest[t], f=flow[t];
32 if( f && !dep[v] ) {
33 dep[v] = dep[u]+1;
34 qu[++ed] = v;
35 }
36 }
37 }
38 return dep[dst];
39 }
40 int dfs( int u, int a ) {
41 if( u==dst || a==0 ) return a;
42 int remain=a, past=0, na;
43 for( int &t=cur[u]; ~t; t=next[t] ) {
44 int v=dest[t], &f=flow[t], &vf=flow[t^1];
45 if( f && dep[v]==dep[u]+1 && (na=dfs(v,min(remain,f))) ) {
46 f -= na;
47 vf += na;
48 remain -= na;
49 past += na;
50 if( !remain ) break;
51 }
52 }
53 return past;
54 }
55 int maxflow() {
56 int f = 0;
57 while( bfs() ) {
58 for( int u=1; u<=n; u++ ) cur[u]=head[u];
59 f += dfs(src,oo);
60 }
61 return f;
62 }
63 void print( int *ans ) {
64 for( int e=0; e<etot; e++ )
65 if( eid[e]!=-1 ) ans[eid[e]]+=flow[e^1];
66 }
67 }D;
68 struct Bottop {
69 int n;
70 int head[N], dest[M], bot[M], top[M], next[M], eid[M], etot;
71 int si[N], so[N], sum;
72
73 void init( int n ) {
74 this->n = n;
75 memset( head, -1, sizeof(head) );
76 memset( si, 0, sizeof(si) );
77 memset( so, 0, sizeof(so) );
78 etot = 0;
79 }
80 void adde( int id, int u, int v, int b, int t ) {
81 eid[etot]=id, next[etot]=head[u], bot[etot]=b, top[etot]=t, dest[etot]=v;
82 head[u]=etot++;
83 }
84 void build( int *ans ) {
85 int src=n+1, dst=n+2;
86 D.init( dst, src, dst );
87 for( int u=1; u<=n; u++ )
88 for( int t=head[u]; ~t; t=next[t] ) {
89 int v=dest[t];
90 ans[eid[t]] += bot[t];
91 si[v] += bot[t];
92 so[u] += bot[t];
93 D.adde( eid[t], u, v, top[t]-bot[t] );
94 }
95 for( int u=1; u<=n; u++ ) {
96 if( so[u]>si[u] )
97 D.adde( -1, u, dst, so[u]-si[u] );
98 else if( si[u]>so[u] ) {
99 D.adde( -1, src, u, si[u]-so[u] );
100 sum += si[u]-so[u];
101 }
102 }
103 }
104 bool ok() { return D.maxflow()==sum; }
105 }B;
106
107 int n, m;
108 int ans[M];
109
110 int main() {
111 scanf( "%d%d", &n, &m );
112 B.init(n);
113 for( int i=1,u,v,b,t; i<=m; i++ ) {
114 scanf( "%d%d%d%d", &u, &v, &b, &t );
115 B.adde( i, u, v, b, t );
116 }
117 B.build(ans);
118 bool ok = B.ok();
119 printf( "%s\n", ok ? "YES" : "NO" );
120 if( ok ) {
121 D.print( ans );
122 for( int i=1; i<=m; i++ )
123 printf( "%d\n", ans[i] );
124 }
125 }
