#include<iostream>

#include<cstdio>

#include<cmath>

#include<cstring>

#include<algorithm>

#include<set>

#include<map>

#include<queue>

#include<stack>

#include<vector>

using namespace std;

typedef long long ll;

typedef pair<int,int> P;

#define PI acos(-1.0)

const int maxn=1e5+,maxm=1e5+,inf=0x3f3f3f3f,mod=1e9+;

const ll INF=1e18+;

struct edge

{

    int from,to,cap,flow;

};

vector<edge>es;

vector<int>G[maxn];

bool vis[maxn];

int dist[maxn];

int iter[maxn];

void init(int n)

{

    for(int i=; i<=n+; i++) G[i].clear();

    es.clear();

}

void addedge(int from,int to,int cap)

{

    es.push_back((edge)

    {

        from,to,cap,

    });

    es.push_back((edge)

    {

        to,from,,

    });

    int x=es.size();

    G[from].push_back(x-);

    G[to].push_back(x-);

}

bool BFS(int s,int t)

{

    memset(vis,,sizeof(vis));

    queue <int> Q;

    vis[s]=;

    dist[s]=;

    Q.push(s);

    while(!Q.empty())

    {

        int u=Q.front();

        Q.pop();

        for (int i=; i<G[u].size(); i++)

        {

            edge &e=es[G[u][i]];

            if (!vis[e.to]&&e.cap>e.flow)

            {

                vis[e.to]=;

                dist[e.to]=dist[u]+;

                Q.push(e.to);

            }

        }

    }

    return vis[t];

}

int DFS(int u,int t,int f)

{

    if(u==t||f==) return f;

    int flow=,d;

    for(int &i=iter[u]; i<G[u].size(); i++)

    {

        edge &e=es[G[u][i]];

        if(dist[u]+==dist[e.to]&&(d=DFS(e.to,t,min(f,e.cap-e.flow)))>)

        {

            e.flow+=d;

            es[G[u][i]^].flow-=d;

            flow+=d;

            f-=d;

            if (f==) break;

        }

    }

    return flow;

}

int Maxflow(int s,int t)

{

    int flow=;

    while(BFS(s,t))

    {

        memset(iter,,sizeof(iter));

        int d=;

        while(d=DFS(s,t,inf)) flow+=d;

    }

    return flow;

}

int in[maxn],out[maxn];

int l[maxn];

int main()

{

    int n,m;

    scanf("%d%d",&n,&m);

    /**有源汇点*/

    int s,t;

    scanf("%d%d",&s,&t);

    memset(in,,sizeof(in));

    memset(out,,sizeof(out));

    init(n);

    for (int i=; i<=m; i++)

    {

        int u,v,r;

        scanf("%d %d %d %d",&u,&v,&l[i],&r);

        out[u]+=l[i],in[v]+=l[i];

        addedge(u,v,r-l[i]);

    }

    /**有源汇点有下界*/

    addedge(t,s,inf);

    /**有下界添加新源点0，汇点n+1*/

    int ss=,tt=n+;

    int sum=;

    for(int i=; i<=n; i++)

    {

        if(in[i]>out[i])

        {

            addedge(ss,i,in[i]-out[i]);

            sum+=in[i]-out[i];

        }

        else if(in[i]<out[i])

            addedge(i,tt,out[i]-in[i]);

    }

    /**无下界直接用s，t求最大流*/

    if(Maxflow(ss,tt)!=sum) puts("NO");

    else

    {

        puts("YES");

        /**有源汇点*/

        int ans=-es[*m+].flow;

        es[*m+].flow=;

        es[*m].flow=;

        es[*m].cap=;

        ans+=Maxflow(s,t);///ans-=Maxflow(t,s);///最小流

        printf("%d\n",ans);

        /**无源汇点：可以理解成水管形成循环*/

        for(int i=; i<m*; i+=)

            printf("%d\n",es[i].flow+l[i/+]);///每根水管的流量情况

    }

    return ;

}