1 #include<bits/stdc++.h>
 2 using namespace std;
 3 #define ll long long
 4 #define gc(a) a=getchar()
 5 #define pc(a) putchar(a)
 6 ll read(){
 7     char c;ll x=0;bool flag=0;gc(c);
 8     while(c<'0'||c>'9'){if(c=='-') flag=1;gc(c);}
 9     while(c>='0'&&c<='9'){x=(x<<3
 
)+(x<<1)+(c^48),gc(c);}
10     return flag?-x:x;
11 }
12 void pr(ll x){
13     if(x<0){x=-x;pc('-');}
14     if(x>9) pr(x/10);
15     pc(x%10+48);
16 }
17 
18 const int maxn = 2050;
19 const int maxm = 10050;
20 const int INF = 2147483647;
21 long long ans = 0,les[maxn];
22 int cnt = -1;
23 int head[maxn];
 
24 int s,t,n,m;
25 int pre[maxn];
26 bool vis[maxn];
27 queue<int> que;
28 
29 struct Edge{
30     int v,nex;
31     long long c;
32     
33     Edge(){
34         this->v = 0;
35         this->nex = -1;
36         this->c = 0;
37     }
38     Edge(int v,int nex,long long c):
39     v(v),nex(nex),c(c){}
 
40 }edge[maxm * 2];
41 
42 void edgepush(int u,int v,long long c){
43     edge[++cnt] = Edge(v,head[u],c);
44     head[u] = cnt;
45     edge[++cnt] = Edge(u,head[v],0);
46     head[v] = cnt;
47 }
48 
49 bool bfs(){
50     int u,v;
51     for(int i = 1;i <= n;i++)
52         vis[i] = 0;
53     while(!que.empty()) que.pop();
54     que.push(s);
55     les[s] = INF;
56     vis[s] = 1;
57     while(!que.empty()){
58         u = que.front();
59         que.pop();
60         for(int i = head[u]; ~i ;i = edge[i].nex){
61             v = edge[i].v;
62             if(vis[v] || !edge[i].c) continue;
63             pre[v] = i;
64             les[v] = min(les[u],edge[i].c);
65             if(v == t) return 1;
66             que.push(v);
67             vis[v] = 1;
68         }
69     }
70     return 0;
71 }
72 
73 void EK(){
74     while(bfs()){
75         int ite = 0;
76         ans += les[t];
77         for(int i = t;i != s;i = edge[pre[i]^1].v){
78             ite = pre[i];
79             edge[ite].c -= les[t];
80             edge[ite^1].c += les[t];
81         }
82     }
83 }
84 int main(){
85     int u,v;
86     long long c;
87     n = read(),m = read(),
88     s = read(),t = read();
89     for(int i = 1;i <= n;i++)
90         head[i] = -1;
91     for(int i = 0;i < m;i++){
92         u = read(),
93         v = read(),
94         c = read();
95         edgepush(u,v,c);
96     }
97     EK();
98     pr(ans);
99 }