#include<bits/stdc++.h>
#define int long long
using namespace std;
const int N=1e18;
int n,m,s,t,w[210][210],dep[210],ans;
vector<int>v[210];
bool bfs(){
	for(int i=1;i<=n;i++)dep[i]=N;
	dep[s]=0;
	queue<int>q;
	q.push(s);
	while(!q.empty()){
		int f=q.front();
		q.pop();
		for(int i=0;i<v[f].size();i++){
			if(w[f][v[f][i]]<=0||dep[v[f][i]]<N)continue;
			q.push(v[f][i]);
			dep[v[f][i]]=dep[f]+1;
		}
	}
	if(dep[t]<N)return 1;
	return 0;
}
int dfs(int u,int sum){
	if(u==t)return sum;
//		cout<<u<<endl;
	int k=0,num=0;
	for(int i=0;i<v[u].size()&&sum>0;i++){
		if(w[u][v[u][i]]<=0||dep[v[u][i]]!=dep[u]+1)continue;
		k=dfs(v[u][i],min(sum,w[u][v[u][i]]));
		if(k==0)dep[v[u][i]]=0;
		w[u][v[u][i]]-=k;
		w[v[u][i]][u]+=k;
//		cout<<u<<" "<<v[u][i]<<" "<<k<<endl;
		num+=k;
		sum-=k;
	}
	return num;
}
signed main() {
//	ios::sync_with_stdio(0);
//	cin.tie(0);
//	cout.tie(0);
	cin>>n>>m>>s>>t;
	for(int i=1;i<=m;i++){
		int x,y,z;
		cin>>x>>y>>z;
		v[x].push_back(y);
		v[y].push_back(x);
		w[x][y]=max(w[x][y],z);
	}
	while(bfs()){
		ans+=dfs(s,N);
	}
	cout<<ans;
	return 0;
}