#include<bits/stdc++.h>
using namespace std;
int n,m,s,t;
vector< vector<int> > e;
int fordFulkerson(int s, int t){	
	int u,v;
	int max_flow=0;
	vector<vector<int>> rGraph=e; 
	while(true){
		vector<int> parent(n,-1);  
		queue<int> q;
		q.push(s);
		parent[s]=-2;
		while (!q.empty() && parent[t]==-1){
			int cur=q.front();
			q.pop();
			for(int i=1;i<=n;i++){
				if(rGraph[cur][i]>0 && parent[i]==-1){
					parent[i]=cur;
					q.push(i);
				}
			}
		}
		if(parent[t]==-1) break; 
		int path_flow=INT_MAX; 
		for(v=t;v!=s;v=parent[v]){
			u=parent[v]; 
			path_flow=min(path_flow, rGraph[u][v]); 
		}
		for(v=t;v!=s;v=parent[v]){
			u=parent[v]; 
			rGraph[u][v]-=path_flow; 
			rGraph[v][u]+=path_flow;
		}	
		max_flow+=path_flow;
	}	
	return max_flow;
}
int main(){
	scanf("%d%d%d%d",&n,&m,&s,&t);
	e.resize(n + 1, vector<int>(n + 1, 0));
	for(int i=1;i<=m;i++){
		int u,v,w;
		scanf("%d%d%d",&u,&v,&w);
		e[u][v]=w;
	}
	cout<<fordFulkerson(s,t);
	return 0;
}