#include<bits/stdc++.h>
using namespace std;

#define poly vector
#define N 201
#define ll long long

const int inf=1e9;
int n,m;
ll graph[N][N],pre[N],fl[N];

ll bfs(int s,int t){
	memset(pre,-1,sizeof(pre));
	fl[s]=inf;
	pre[s]=0;
	queue<int> q;q.push(s);
	while(q.size()){
		int u=q.front();q.pop();
		if(u==t)break;
		for(int i=1;i<=n;i++){
			if(i!=s&&graph[u][i]>0&&pre[i]==-1){
				pre[i]=u;q.push(i);fl[i]=min(fl[i],graph[u][i]);
			} 
		}
	}
	if(pre[t]==-1)return -1;
	return fl[t];
}

ll Maxflow(int s,int t){
	ll Maxfl=0;
	while(1){
		ll flow=bfs(s,t);
		if(flow==-1)break;
		int cur=t;
		while(cur!=s){
			int fa=pre[cur];
			graph[fa][cur]-=flow;
			graph[cur][fa]+=flow;
			cur = fa;
		}
		Maxfl+=flow;
	}
	return Maxfl;
}
int main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	cout.tie(nullptr);
	int s,t;
	cin>>n>>m>>s>>t;
	memset(graph,0,sizeof(graph));
	for(int i=0;i<m;i++){
		int u,v,w;
		cin>>u>>v>>w;
		graph[u][v]+=w;
	}
	cout<<Maxflow(s,t);
	return 0;
}