#include<iostream>
#include<iostream>
#include<queue>
#include<cstring>
using namespace std;
struct edge{int x, y, c, pre, other;}a[41000];int alen, last[21000], h[21000], st, ed;
void  ins(int x, int y, int c)
{
	a[++alen]=edge{x, y, c, last[x], alen+1};last[x]=alen;
	a[++alen]=edge{y, x, 0, last[y], alen-1};last[y]=alen;
}
bool bh()
{
	memset(h, 0, sizeof(h)); h[st]=1;
	queue<int>q;q.push(st);
	while(!q.empty())
	{
		int x=q.front();
		for(int k=last[x];k>0;k=a[k].pre)
		{
			int y=a[k].y;
			if(h[y]==0&&a[k].c>0)
			{
				h[y]=h[x]+1; 
				q.push(y);
			}
		}
		q.pop();
	}
	return h[ed]>0;
}
int findflow(int x, int f)
{
	if(x==ed) return f; 
	int sx=0;
	for(int k=last[x];k>0;k=a[k].pre)
	{
		int y=a[k].y;
		if(a[k].c>0&&sx<f&&h[y]==(h[x]+1)) 
		{
			int sy=findflow(y, min(a[k].c, f-sx));
			a[k].c-=sy; a[a[k].other].c+=sy;
			sx+=sy;
		}
	}
	if(sx==0) h[x]=0;
	return sx;
}
int main()
{
	int n, m;
	scanf("%d%d%d%d", &n, &m, &st, &ed);
	alen=0;memset(last, 0, sizeof(last));
	for(int i=1;i<=m;i++)
	{
		int x, y, c;
		scanf("%d%d%d", &x, &y, &c);
		ins(x, y, c);
	}
	long long s=0;
	while(bh()) 
	{
		s+=findflow(st, 0x15f);
	}
	printf("%d\n", s);
	return 0;
}