#include<bits/stdc++.h>
using namespace std;
const int INF=0x7fffffff;
struct Edge{
	int to,next,flow;
}edge[10010];
int head[210],dep[210];
int tot=1,s,t;
void add(int from,int to,int flow){
	edge[++tot].to=to,edge[tot].next=head[from],edge[tot].flow=flow;
	head[from]=tot;
	edge[++tot].to=from,edge[tot].next=head[to],edge[tot].flow=0;
	head[to]=tot;
}
bool bfs(){
	memset(dep,0,sizeof(dep));
	queue<int>q;
	q.push(s),dep[s]=1;
	while(!q.empty()){
		int u=q.front();
		q.pop();
		for(int i=head[u];i;i=edge[i].next){
			int v=edge[i].to,f=edge[i].flow;
			if(dep[v]==0&&f>0){
				q.push(v);
				dep[v]=dep[u]+1;
				if(v==t)return true;
			}
		}
	}
	return false;
}
int dfs(int u,int flow){
	if(u==t){
		return flow;
	}
	int rest=flow;
	for(int i=head[u];i&&rest;i=edge[i].next){
		int v=edge[i].to,f=edge[i].flow;
		if(dep[v]==dep[u]+1&&f>0){
			int ff=dfs(v,min(rest,f));
			if(ff=0)dep[v]=0;
			rest-=ff;
			edge[i].flow-=ff;
			edge[i^1].flow+=ff;
		}
	}
	return flow-rest;
}
int Dinic(){
	int mxf=0,flow;
	while(bfs()){
		while(flow=dfs(s,INF)){
			mxf+=flow;
		}
	}
	return mxf;
}
int main(){
	int n,m;
	cin>>n>>m>>s>>t;
	for(int i=1;i<=m;i++){
		int u,v,w;
		cin>>u>>v>>w;
		add(u,v,w);
	}
	cout<<Dinic()<<endl;
	return 0;
}