#include<bits/stdc++.h>
#define N 205
#define int long long
using namespace std;

struct E {
	int ed,c;
};
vector<E> a[N],b[N]; // a 正边，b 反边 
queue<int> q;

int n,m,s,t,ans;
int d[N];

bool bfs() {
	memset(d,0,sizeof(d));
	while(!q.empty()) q.pop();
	q.push(s); d[s] = 1;
	while(!q.empty()) {
		int fr = q.front(); q.pop();
		for(auto j : a[fr]) {
			int v = j.ed, c = j.c;
			if(!d[v] && c) {
				d[v] = d[fr] + 1;
				if(v == t) return true;
				q.push(v);
			}
		}
	}
	return false;
}

int dfs(int u,int minf) {
	if(u == t) return minf;
	int sum = 0;
	for(int i = 0; i < a[u].size(); i ++) {
		int v = a[u][i].ed, w = a[u][i].c;
		if(d[v] == d[u]+1 && w) {
			int f = dfs(v,min(minf,w));
			a[u][i].c -= f;
			b[v][i].c += f;
			minf -= f;
			sum += f;
			if(minf <= 0) break;
		}
	}
	if(sum == 0) d[u] = 0;
	return sum;
}
signed main() {
	
	cin >> n >> m >> s >> t;
	for(int i = 1; i <= m; i ++) {
		int u,v,w;
		cin >> u >> v >> w;
		a[u].push_back({v,w});	
		b[v].push_back({u,0});	
	}
	
	int Max = 1 << 31;
	while(bfs()) {
		ans += dfs(s,Max);
	}
	cout << ans;
	
	return 0;
}