#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll N=205,M=5005,INF=0x3f3f3f3f3f3f3f3f; 
ll n,m,s,t,tot=1,hd[N],d[N],ans;
struct edge{ll t,c,nxt;}es[M<<1];
void add(ll u,ll v,ll c){
	es[++tot]=(edge){v,c,hd[u]};hd[u]=tot;
	es[++tot]=(edge){u,0,hd[v]};hd[v]=tot;
}
bool bfs(){
	memset(d,0,sizeof(d));
	queue<ll>q;
	q.push(s);d[s]=1;
	for(ll x;!q.empty();){
		x=q.front();q.pop();
		for(ll i=hd[x];i;i=es[i].nxt)
			if(es[i].c&&!d[es[i].t]){
				q.push(es[i].t);
				d[es[i].t]=d[x]+1;
				if(es[i].t==t)return 1;
			}
	}
	return 0;
}
ll dinic(ll x,ll flow){
	if(x==t)return flow;
	ll rest=flow,k;
	for(ll i=hd[x];i;i=es[i].nxt)
		if(es[i].c&&d[es[i].t]==d[x]+1){
			k=dinic(es[i].t,min(rest,es[i].c));
			es[i].c-=k,es[i^1].c+=k;
			rest-=k;
		}
	if(flow-rest==0)d[x]=-1;
	return flow-rest;
}
int main(){
	scanf("%lld%lld%lld%lld",&n,&m,&s,&t);
	for(ll i=1,u,v,c;i<=m;i++){
		scanf("%lld%lld%lld",&u,&v,&c);
		add(u,v,c);
	}
	for(ll flow=0;bfs();)while((flow=dinic(s,INF)))ans+=flow;
	printf("%lld",ans);
	return 0;
}