#include<cstdio>
#include<cstring>
using  namespace  std;
struct  node
{
	int  y,c,next,other;
}a[30000];int  last[410],len,n,m;
struct  bian
{
	int  x,y,l,r,id;
}b[30000];
struct  node1
{
	int  a[410],len;
}stl,edl;int  stt,edd,rd[410],cd[410];
void  ins(int  x,int  y,int  c)
{
	len++;
	a[len].y=y;a[len].c=c;a[len].next=last[x];last[x]=len;
	len++;
	a[len].y=x;a[len].c=0;a[len].next=last[y];last[y]=len;
	a[len].other=len-1;
	a[len-1].other=len;
}
int  list[410],head,tail,h[410];
bool  bt()
{
	memset(h,0,sizeof(h));h[stt]=1;
	head=1;tail=2;list[head]=stt;
	while(head!=tail)
	{
		int  x=list[head];
		for(int  k=last[x];k;k=a[k].next)
		{
			int  y=a[k].y;
			if(h[y]==0  &&  a[k].c>0)
			{
				h[y]=h[x]+1;
				list[tail++]=y;
			}
		}
		head++;
	}
	return  h[edd]!=0;
}
inline  int  mymin(int  x,int  y){return  x<y?x:y;}
int  find(int  x,int  f)
{
	if(x==edd)return  f;
	int  t=0,ans=0;
	for(int  k=last[x];k;k=a[k].next)
	{
		int  y=a[k].y;
		if(a[k].c>0  &&  h[y]==h[x]+1  &&  ans<f)
		{
			ans+=t=find(y,mymin(f-ans,a[k].c));
			a[k].c-=t;a[a[k].other].c+=t;
		}
	}
	return  ans;
}
int  main()
{
	scanf("%d%d",&n,&m);
	stt=0;edd=n+1;
	for(int  i=1;i<=m;i++)
	{
		scanf("%d%d%d%d",&b[i].x,&b[i].y,&b[i].l,&b[i].r);
		ins(b[i].x,b[i].y,b[i].r-b[i].l);rd[b[i].y]+=b[i].l;cd[b[i].x]+=b[i].l;b[i].id=len;
	}
	for(int  i=1;i<=n;i++)
	{
		int  p=rd[i]-cd[i];
		if(p>=0)
		{
			ins(stt,i,p);
			stl.a[++stl.len]=len-1;
		}
		else
		{
			ins(i,edd,-p);
			edl.a[++edl.len]=len-1;
		}
	}
	int  ans=0;
	while(bt()==true)
	{
		ans+=find(stt,999999999);
	}
	bool  bk=true;
	for(int  i=1;i<=stl.len;i++)
	{
		if(a[stl.a[i]].c!=0)
		{
			bk=false;
			break;
		}
	}
	for(int  i=1;i<=edl.len;i++)
	{
		if(a[edl.a[i]].c!=0)
		{
			bk=false;
			break;
		}
	}
	if(bk==false)printf("NO\n");
	else
	{
		printf("YES\n");
		for(int  i=1;i<=m;i++)printf("%d\n",b[i].l+a[b[i].id].c);
	}
	return  0;
}