#include <bits/stdc++.h>
using namespace std;
int n,m,s,t,i,a,b;
long long ans;
int w[210][210],de[201],q[201],top,rea;
bool bfs()
{
	memset(de,0,sizeof(de));
	top=rea=1;
	q[1]=s;
	de[s]=1;
	while(top<=rea)
	{
		for(i=1;i<=n;i++)
		{
			if(de[i]==0&&w[q[top]][i]!=0)
			{
				de[i]=de[q[top]]+1;
				q[rea+1]=i;
				rea++;
			}
		}
		top++;
	}
	return de[t];
}
int dfs(int a,int minn)
{
	if(a==t)
	{
		ans+=minn;
		return minn;
	}
    else
    {
    	int j,ret=0,g;
    	for(j=1;j<=n;j++)
    	{
    		if(ret==minn) break;
    		if(w[a][j]!=0&&de[j]==de[a]+1)
    		{
    			g=dfs(j,min(minn-ret,w[a][j]));
    			w[a][j]-=g;
    			w[j][a]+=g;
    			ret+=g;
			}
		}
		return ret;
	}
}
int main()
{
	freopen("P3376_8.in","r",stdin);
	cin>>n>>m>>s>>t;
	for(i=0;i<m;i++)
	{
		cin>>a>>b;
		cin>>w[a][b];
	}
	while(bfs())
		dfs(s,0x7fffffff); 
	cout<<ans;
	return 0;
 }