#include<bits/stdc++.h>

 #define rep(i,x,y) for (int i=(x);i<=(y);i++)

 #define ll long long

 #define inf 1000000001

 #define y1 y1___

 using namespace std;

 char gc(){

     static char buf[],*p1=buf,*p2=buf;

     return p1==p2&&(p2=(p1=buf)+fread(buf,,,stdin),p1==p2)?EOF:*p1++;

 }

 #define gc getchar

 ll read(){

     char ch=gc();ll x=;int op=;

     for (;!isdigit(ch);ch=gc()) if (ch=='-') op=-;

     for (;isdigit(ch);ch=gc()) x=(x<<)+(x<<)+ch-'';

     return x*op;

 }

 #define N 60005

 #define M 130005+N<<1

 int n,m,cnt=,s_,t_,s,t,head[N],d[N],vis[N],cur[N];

 struct edge{int to,nxt,c;}e[M];

 void adde(int x,int y,int c){

     e[++cnt].to=y;e[cnt].nxt=head[x];head[x]=cnt;

     e[cnt].c=c;

 }

 void ins(int x,int y,int z){

     adde(x,y,z);adde(y,x,);

 }

 bool bfs(){

     queue<int> q;q.push(s);

     rep (i,,t) vis[i]=-;vis[s]=;

     while (!q.empty()){

         int u=q.front();q.pop();

         for (int i=head[u];i;i=e[i].nxt){

             int v=e[i].to;

             if (e[i].c&&vis[v]==-) vis[v]=vis[u]+,q.push(v);

         }

     }

     return vis[t]!=-;

 }

 int dfs(int u,int flow){

     if (u==t) return flow;

     int w,used=;

     for (int &i=cur[u];i;i=e[i].nxt){

         int v=e[i].to;

         if (e[i].c&&vis[v]==vis[u]+){

             w=dfs(v,min(flow-used,e[i].c));

             e[i].c-=w,e[i^].c+=w,used+=w;

             if (used==flow) return used;

         }

     }

     if (!used) vis[u]=-;

     return used;

 }

 int dinic(){

     int ret=;

     while (bfs()){

         memcpy(cur,head,sizeof(cur));//当前弧优化

         ret+=dfs(s,inf);

     }

     return ret;

 }

 int main(){

     n=read(),m=read(),s_=read(),t_=read();

     rep (i,,m){

         int x=read(),y=read(),a=read(),b=read();

         ins(x,y,b-a);d[x]-=a,d[y]+=a;

     }

     s=n+,t=n+;

     rep (i,,n) if (d[i]>) ins(s,i,d[i]);else ins(i,t,-d[i]);

     dinic();//不加边直接跑，尽可能跑完

     ins(t_,s_,inf);

     dinic();//加边以后再跑

     for (int i=head[s];i;i=e[i].nxt) if (vis[e[i].to]!=-) return puts("please go home to sleep"),;//判无解

     printf("%d\n",e[cnt].c);

     return ;

 }