#include<iostream>
#include<cstring>
#include<cstdio>
#include<queue>
using namespace std;
const int MAXN=5100;
const int INF=0x3f3f3f3f;
long long n,m,s,t,u,v,c;
long long head[MAXN],nxt[MAXN<<2],to[MAXN<<2],cap[MAXN<<2],flo[MAXN<<2],cnt;
bool vis[MAXN];
int dep[MAXN],cur[MAXN];
void addEdge(int u,int v,long long c)
{
	cnt++;
	nxt[cnt]=head[u];
	head[u]=cnt;
	to[cnt]=v;
	cap[cnt]=c;
	flo[cnt]=0;
}
bool bfs(int s,int t)
{
	memset(vis,0,sizeof(vis));
	queue<int> q;
	q.push(s);
	vis[s]=1;
	dep[s]=0;
	while(!q.empty())
	{
		int u=q.front();
		q.pop();
		for(int i=head[u];i;i=nxt[i])
		{
			int v=to[i];
			if(!vis[v]&&cap[i]>flo[i])
			{
				vis[v]=1;
				dep[v]=dep[u]+1;
				q.push(v);
			}
		}
	}
	//cout<<vis[t]<<endl;
	return vis[t];
}
long long dfs(int s,int t,int u,long long a)
{
	if(u==t||a==0)
	{
		return a;
	}
	long long flow=0,f;
	cur[u]=head[u];
	for(int i=cur[u];i;i=nxt[i])
	{
		int v=to[i];
		cur[u]=i;
		if(dep[u]+1==dep[v]&&(f=dfs(s,t,v,min(a,cap[i]-flo[i])))>0)
		{
			flo[i]+=f;
			flo[i^1]-=f;
			flow+=f;
			a-=f;
			if(a==0)
			{
				break;
			}
		}
	}
	return flow;
}
long long maxFlow(int s,int t)
{
	long long flow=0;
	while(bfs(s,t))
	{
		memset(cur,0,sizeof(cur));
		flow+=dfs(s,t,s,INF);
	}
	return flow;
}
int main()
{
	//freopen("in.txt","r",stdin);
	cin>>n>>m>>s>>t;
	cnt=1;
	for(int i=0;i<m;i++)
	{
		cin>>u>>v>>c;
		addEdge(u,v,c);
		addEdge(v,u,0);
	}
	cout<<maxFlow(s,t);
}