/*
Dinic无源汇上下界可行流
剩下几个板子先咕了下期补
*/
#include<bits/stdc++.h>
#define int long long
using namespace std;
int n,m,s,t,tot=1,maxflow,dis[100010],now[100010],V[100010],flow;
int hed[100010],ver[100010],nxt[100010],edg[100010],ppp[100010];
void add(int a,int b,int c){ver[++tot]=b,nxt[tot]=hed[a],hed[a]=tot,edg[tot]=c;ver[++tot]=a,nxt[tot]=hed[b],hed[b]=tot,edg[tot]=0;
}bool bfs(){queue<int>q;memset(dis,0,sizeof(dis));dis[s]=1;now[s]=hed[s];q.push(s);while(!q.empty()){int u=q.front();q.pop();for(int i=hed[u];i;i=nxt[i]){int v=ver[i];if(dis[v]||(!edg[i])){continue;}now[v]=hed[v];dis[v]=dis[u]+1;q.push(v);if(v==t){return 1;}}}return 0;
}
int dinic(int u,int flow){if(u==t){return flow;}int i,rest=flow;for(i=now[u];i&&rest;i=nxt[i]){int v=ver[i];if(dis[v]!=dis[u]+1||(!edg[i])){continue;}int k=dinic(v,min(rest,edg[i]));if(!k){dis[v]=0; }edg[i]-=k;edg[i^1]+=k;rest-=k;}now[u]=i;return flow-rest;
}
signed main(){cin>>n>>m;s=0,t=n+1;for(int i=1;i<=m;i++){int u,v,p,q;cin>>u>>v>>p>>q;add(u,v,q-p);V[u]-=p,V[v]+=p;ppp[i]=p;}int sum=0;for(int i=1;i<=n;i++){if(V[i]>0){add(s,i,V[i]);sum+=V[i];}if(V[i]<0){add(i,t,-V[i]);}}while(bfs()){while(flow=dinic(s,1e18)){maxflow+=flow;}}if(maxflow<sum){cout<<"No";return 0;}cout<<"Yes\n";for(int i=3;i<=2*m+1;i+=2){cout<<edg[i]+ppp[i/2]<<endl;}return 0;
}