#include <cstdio>
#include <vector>
#include <algorithm>
#include <memory.h>
#define INF 987654321
#define MAX 5010
using namespace std;
int n, m, s, t;
struct EDGE{ int to, cap, rev; };
vector<EDGE> G[MAX];
bool visited[MAX];

int dfs(int v, int t, int f)
{
    if( v == t ) return f;
    visited[v] = true;
    for(int i = 0 ; i < G[v].size() ; i++ )
    {
        EDGE &e = G[v][i];
        if( !visited[e.to] && e.cap > 0 )
        {
            int temp = dfs(e.to, t, min(f, e.cap));
            if( temp > 0 )
            {
                e.cap -= temp;
                G[e.to][e.rev].cap += temp;
                return temp;
            }
        }
    }
    return 0;
}

int max_flow(int s, int t)
{
    int flow= 0, f = 0;
    while(1)
    {
        memset(visited, 0, sizeof(visited));
        f = dfs(s, t, INF);
        if( f == 0 ) return flow;
        flow += f;
    }
}

int main()
{
    freopen(".18.in","r",stdin);
    freopen(".18.out","w",stdout);
    scanf("%d%d%d%d",&n,&m,&s,&t);
    for(int i = 0 ; i < m ; i++ )
    {
        int a, b, w;
        scanf("%d%d%d",&a,&b,&w);
        G[a].push_back((EDGE){b,w,G[b].size()});
        G[b].push_back((EDGE){a,0,G[a].size()-1});
    }
    printf("%d\n", max_flow(s, t));
}