#include<bits/stdc++.h>
#define ll long long 
#define INF 0x3f3f3f3f
using namespace std;
int n, m, s, t;
const int N = 205;
const int M = 5e3+100;
struct Edge
{
	int to, nxt;
	ll flow;
}e[M*2];
int head[N], dis[N], cur[N], ecnt = 1;
void addedge( int u , int v , int fl )
{
	e[++ecnt]=(Edge){v,head[u],fl};head[u] = ecnt;
	e[++ecnt]=(Edge){u,head[v],0};head[v] = ecnt;
}
bool BFS()
{
	
	memset(dis,0x3f,sizeof(dis));
	dis[s] = 0;
	queue<int> q;
	q.push(s);
	while( !q.empty() )
	{
		int u = q.front();
		q.pop();
		for( int i = head[u] ; i ; i = e[i].nxt )
		{
			if( e[i].flow != 0 && dis[e[i].to] == INF)
			{	
				dis[e[i].to] = dis[u]+1;
				q.push(e[i].to); 
			}
		}
	}
	return dis[t] != INF;
}
ll DFS( int u , ll a )
{
	if( u == t || a == 0 ) return a;
	ll ret = 0;
	for( int &i = cur[i] ; i ; i = e[i].nxt )
	{
		if( e[i].flow == 0 || dis[e[i].to] != dis[u]+1 )continue;
		int f = DFS(e[i].to,min(a,e[i].flow));
		if( f )
		{

			ret += f;
			e[i].flow -= f;
			e[i^1].flow += f;
			a -= f;
			if( a == 0 ) return ret;
		}
	}
}
ll Dinic( int S1 , int T1 )
{
	
	s = S1;
	t = T1;
	ll ret = 0;
	while( BFS() )
	{
		memcpy(cur,head,sizeof(cur));
		ret += DFS(s,INF);
	}
	return ret;
}
int main()
{
	memset(head,0,sizeof(head));
	cin >> n >> m >> s >> t;
	int a, b, c;
	for( int i = 1 ; i <= m ; ++i )
	{
		cin >> a >> b >> c;
		addedge(a,b,c);
	}
	ll ans = Dinic(s,t);
	cout << ans << endl;
	
	return 0;
}

不想多言