#include<bits/stdc++.h>
#define LL long long
using namespace std;
const int N=205,M=10005;
const LL INF=(1ll<<60)-1;
struct netflow{
	int n,m,s,t;
	int head[N],nxt[M],tot,ver[M];
	LL w[M];
	
	void add_(int x,int y,LL z){
		ver[++tot]=y,nxt[tot]=head[x],head[x]=tot,w[tot]=z;
		ver[++tot]=x,nxt[tot]=head[y],head[y]=tot,w[tot]=0;
	}
	int q[N],lev[N],cur[N];
	bool bfs(){
		for(int i=1;i<=n;i++){
			lev[i]=0,cur[i]=head[i];
		}
		lev[s]=1;
		int l,r;
		q[l=r=1]=s;
		while(l<=r){
			int x=q[l++];
			for(int i=head[x];i;i=nxt[i]){
				int y=ver[i];
				if(w[i]&&!lev[y]){
					lev[y]=lev[x]+1;
					q[++r]=y;
					if(y==t)return 1;
				}
			}
		}
		return 0;
	}
	int dfs(int x,LL flow){
		if(x==t)return flow;
		LL res=0;
		for(int &i=cur[x];i;i=nxt[i]){
			int y=ver[i];
			if(w[i]&&lev[y]==lev[x]+1){
				int k=dfs(y,min(flow,w[i]));
				flow-=k;
				res+=k;
				w[i]-=k;
				w[i^1]+=k;
				if(!flow)break;
			}
		}
		if(!res)lev[x]=0;
		return res;
	}
	LL dinic(){
		LL ans=0;
		while(bfs()){
			ans+=dfs(s,INF);
		}
		return ans;
	}
}T;
int main(){
	T.tot=1;
	scanf("%d%d%d%d",&T.n,&T.m,&T.s,&T.t);
	for(int i=1;i<=T.m;i++){
		int x,y;
		LL z;
		scanf("%d%d%lld",&x,&y,&z);
		T.add_(x,y,z);
	}
	cout<<T.dinic();
	return 0;
}