#include <cstdio>

#include <cstring>

#include <algorithm>

#include <queue>

using namespace std;

const int MAX_NODE = 10010, MAX_EDGE = 100010 * 2, INF=0x3f3f3f3f;

#define LOOP(i, n) for(int i=1; i<=n; i++)

struct Dinic

{

private:

	struct Node;

	struct Edge;

	struct Node

	{

		int Level, Id;

		Edge *Head, *DfsFrom;

	}_nodes[MAX_NODE], *Start, *Target;

	int _vCount;

	struct Edge

	{

		Node *From, *To;

		Edge *Next, *Rev;

		int Cap;

	}*_edges[MAX_EDGE];

	int _eCount;

	Edge *NewEdge()

	{

		return _edges[++_eCount] = new Edge();

	}

	Edge *AddEdge(Node *from, Node *to, int cap)

	{

		Edge *e = NewEdge();

		e->From = from;

		e->To = to;

		e->Cap = cap;

		e->Next = from->Head;

		from->Head = e;

		return e;

	}

	bool Bfs()

	{

		LOOP(i, _vCount)

			_nodes[i].Level = 0;

		Start->Level = 1;

		static queue<Node*> q;

		q.push(Start);

		while (!q.empty())

		{

			Node *cur = q.front();

			q.pop();

			for (Edge *e = cur->Head; e; e = e->Next)

			{

				if (!e->To->Level && e->Cap)

				{

					e->To->Level = cur->Level + 1;

					q.push(e->To);

				}

			}

		}

		return Target->Level;

	}

	int Dfs(Node *cur, int limit)

	{

		if (cur == Target)

			return limit;

		if (limit == 0)

			return 0;

		int curTake = 0;

		for (Edge *e = cur->DfsFrom; e; e = cur->DfsFrom = e->Next)

		{

			if (e->Cap && e->To->Level == cur->Level + 1)

			{

				int nextTake = Dfs(e->To, min(limit - curTake, e->Cap));//易忘点：-curTake

				e->Cap -= nextTake;

				e->Rev->Cap += nextTake;

				curTake += nextTake;

			}

			if (limit - curTake == 0)//易忘点

				break;

		}

		return curTake;

	}

public:

	void Build(int uId, int vId, int cap)

	{

		Node *u = _nodes + uId, *v = _nodes + vId;

		u->Id = uId;

		v->Id = vId;

		Edge *e1 = AddEdge(u, v, cap), *e2 = AddEdge(v, u, 0);

		e1->Rev = e2;

		e2->Rev = e1;

	}

	int Proceed()

	{

		int ans = 0;

		while (Bfs())

		{

			LOOP(i, _vCount)

				_nodes[i].DfsFrom = _nodes[i].Head;

			ans += Dfs(Start, INF);

		}

		return ans;

	}

	Dinic() {}

	Dinic(int totNode, int sId, int tId):_vCount(totNode),Start(_nodes+sId),Target(_nodes+tId)

	{

		memset(_nodes, 0, sizeof(_nodes));

		memset(_edges, 0, sizeof(_edges));

	}

};

int main()

{

	//g.Test();

#ifdef _DEBUG

	freopen("c:\\noi\\source\\input.txt", "r", stdin);

#endif

	int m, vCount, sId, tId;

	scanf("%d%d%d%d", &vCount, &m, &sId, &tId);

	static Dinic g(vCount, sId, tId);

	int uId, vId, cap;

	for (int i = 0; i < m; i++)

	{

		scanf("%d%d%d", &uId, &vId, &cap);

		g.Build(uId, vId, cap);

	}

	int ans;

	ans = g.Proceed();

	printf("%d\n", ans);

}