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

const int N = 405;
const int inf = 0x3f3f3f3f;

int n, m, s, t;
int tot, head[N], ver[N], edge[N], nxt[N];
bool vis[N];

void add(int x, int y, int z) {
	ver[++tot] = y, edge[tot] = z, nxt[tot] = head[x], head[x] = tot;
	ver[++tot] = x, edge[tot] = 0, nxt[tot] = head[y], head[y] = tot;
}

int dfs(int x, int flow) {
	if (x == t) return flow;
	vis[x] = 1;
	for (int i = head[x]; i; i = nxt[i]) {
		int y = ver[i], z = edge[i], c;
		if (z > 0 && !vis[y]) {
			c = dfs(y, min(flow, z));
			if (c == -1) continue;
			edge[i] -= c, edge[i ^ 1] += c;
			return c;
		}
	}
	return -1;
}

int ff() {
	int ans = 0, c;
	while ((c = dfs(s, inf)) != -1) {
		memset(vis, 0, sizeof(vis));
		ans += c;
	}
	return ans;
}

signed main() {
	ios::sync_with_stdio(false);
	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;
		add(x, y, z);
	}
	cout << ff() << endl;
	return 0;
}