#include<bits/stdc++.h>
#define INF 0x3f3f3f3f
#define LL long long
#define mem(x,y) memset(x,y,sizeof(x))

using namespace std;

const int MAXN = 205;
const int MAXM = 5005;
int n, m, s, t, tot = 1;
int lv[MAXN * 2], cur[MAXN * 3];
struct node {
	int u, v, next;
	LL w;
}E[MAXM * 3];
int first[MAXM * 3];

void add(int u, int v, LL w) {
	E[++tot].u = u;
	E[tot].v = v;
	E[tot].w = w;
	E[tot].next = first[u];
	first[u] = tot;
}

bool bfs() {
	memset(lv, -1, sizeof(lv));
	lv[s] = 0;
	for(int i = 1; i <= tot; i++) cur[i] = first[i];
	queue<int> q;
	q.push(s);
	while(!q.empty()) {
		int p = q.front();
		q.pop(); 
		//cout << p << endl;
		for(int i = first[p]; i != -1; i = E[i].next) {
			int to = E[i].v;
			LL vol = E[i].w;
			//cout << "->" << to << " " << vol << endl;
			if(vol > 0 && lv[to] == -1)
				lv[to] = lv[p] + 1, q.push(to);
		}
	}
	return lv[t] != -1;
}

LL dfs(int p = s, LL flow = INF) {
	if(p == t) return flow;
	LL rmn = flow;
	for(int i = cur[p]; i != -1 && rmn != 0; i = E[i].next) {
		cur[p] = i;
		int to = E[i].v;
		LL vol = E[i].w;
		if(vol > 0 && lv[to] == lv[p] + 1) {
			LL c = dfs(to, min(vol, rmn));
			rmn -= c;
			E[i].w -= c;
			E[i ^ 1].w += c;
		}
	}
	return flow - rmn;
}

LL dinic() {
	LL ans = 0;
	while(bfs()) {
		ans += dfs();
	}
	return ans;
}

int main() {
	memset(first, -1, sizeof(first));
	cin >> n >> m >> s >> t;
	for(int i = 1; i <= m; i++) {
		int u, v, w;
		cin >> u >> v >> w;
		add(u, v, w);
		add(v, u, 0);
	}
	//for(int i = first[4]; i != -1; i = E[i].next) cout << E[i].v << endl;
	cout << dinic() << endl;
	return 0;
}