#include <iostream>

#include <cstdio>

#include <cstring>

#include <queue>

#define mem(a,b) memset(a,b,sizeof(a))

using namespace std;

const int maxn = , INF = 0x7fffffff;

int d[maxn], head[maxn];

int n, m, s, t;

struct edge{

    int u, v, f, c, next;

}Node[*maxn];

void add(int u, int v, int c, int f, int i)

{

    Node[i].u = u;

    Node[i].v = v;

    Node[i].f = f;

    Node[i].c = c;

    Node[i].next = head[u];

    head[u] = i;

}

int bfs()

{

    queue<int> Q;

    mem(d,);

    Q.push(s);

    d[s] = ;

    while(!Q.empty()){

        int u = Q.front(); Q.pop();

        for(int i=head[u]; i!=-; i=Node[i].next)

        {

            edge e = Node[i];

            if(!d[e.v] && e.c > e.f)

            {

                d[e.v] = d[e.u] + ;

                Q.push(e.v);

            }

        }

    }

    return d[t] != ;

}

int dfs(int u, int cap)

{

//    cout<< u << "  " << cap <<endl;

    if(u == t)

        return cap;

    for(int i=head[u]; i!= -; i=Node[i].next)

    {

        edge e = Node[i];

        if(d[e.v] == d[e.u] +  && e.c > e.f)

        {

            int V = dfs(e.v, min(cap, e.c - e.f));

            if(V > ){

                Node[i].f += V;

                Node[i^].f -= V;

                return V;

            }

        }

    }

    return ;

}

int Dinic()

{

    int ans = ;

    while(bfs())

    {

        while(int l = dfs(s,INF))

            ans += l;

    }

    return ans;

}

int main()

{

    mem(head,-);

    cin>> n >> m >> s >> t;

    int cnt = ;

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

    {

        int u, v, w;

        cin>> u >> v >> w;

        add(u, v, w, , cnt++);

        add(v, u, , , cnt++);

    }

    cout<< Dinic() <<endl;

    return ;

}