1 #include<iostream>
2 #include<cstdio>
3 #include<cmath>
4 #include<algorithm>
5 #include<stack>
6 #include<queue>
7 #include<cstring>
8 #define PAU putchar(' ')
9 #define ENT putchar('\n')
10 #define MSE(a,b) memset(a,b,sizeof(a))
11 #define REN(x) for(ted*e=fch[x];e;e=e->nxt)
12 #define TIL(x) for(int i=1;i<=x;i++)
13 using namespace std;
14 const int maxn=2000+10,maxm=20000+10,inf=1e9;
15 struct zkw{
16 struct ted{int x,y,w,c;ted*nxt,*re;}adj[maxm],*fch[maxn],*ms;
17 int n,S,T,d[maxn],cost,ans;bool inq[maxn],vis[maxn];
18 void init(int n){this->n=n;ms=adj;MSE(vis,false);MSE(inq,false);return;}
19 void add(int x,int y,int w,int c){
20 *ms=(ted){x,y,w,c,fch[x],ms+1};fch[x]=ms++;
21 *ms=(ted){y,x,0,-c,fch[y],ms-1};fch[y]=ms++;
22 return;
23 }
24 bool bfs(){
25 TIL(n)d[i]=inf;queue<int>Q;Q.push(T);d[T]=0;
26 while(!Q.empty()){
27 int x=Q.front();Q.pop();inq[x]=false;REN(x){
28 int v=e->y;if(e->re->w&&d[v]>d[x]+e->re->c){
29 d[v]=d[x]+e->re->c;if(!inq[v])inq[v]=true,Q.push(v);
30 }
31 }
32 }for(ted*e=adj;e!=ms;e++)e->c+=d[e->y]-d[e->x];cost+=d[S];return d[S]!=inf;
33 }
34 int dfs(int x,int aug){
35 if(x==T||!aug)return(ans+=aug*cost,aug);int flow=0,k;vis[x]=true;REN(x){
36 int v=e->y;if(e->w&&!e->c&&!vis[v]&&(k=dfs(v,min(aug,e->w)))){
37 e->w-=k;e->re->w+=k;flow+=k;aug-=k;if(!aug)break;
38 }
39 }return flow;
40 }
41 int mcmf(int S,int T){
42 this->S=S;this->T=T;while(bfs())do MSE(vis,false);while(dfs(S,inf));return ans;
43 }
44 }sol;
45 inline int read(){
46 int x=0,sig=1;char ch=getchar();
47 for(;!isdigit(ch);ch=getchar())if(ch=='-')sig=0;
48 for(;isdigit(ch);ch=getchar())x=10*x+ch-'0';
49 return sig?x:-x;
50 }
51 inline void write(int x){
52 if(x==0){putchar('0');return;}if(x<0)putchar('-'),x=-x;
53 int len=0,buf[15];while(x)buf[len++]=x%10,x/=10;
54 for(int i=len-1;i>=0;i--)putchar(buf[i]+'0');return;
55 }
56 int n,m;
57 int main(){
58 n=read();m=read();sol.init(n);int x,y,w;
59 TIL(m)x=read(),y=read(),w=read(),sol.add(x,y,w,read());write(sol.mcmf(1,n));
60 return 0;
61 }
