#include<bits/stdc++.h>

using namespace std;

const int MAXN =  + ;

const int MAXM =  + ;

const int MAX_INT = ( << );

struct Edge {

    int v, nxt, w;

};

struct Node {

    int v, id;

};

int n, m, ecnt, S , T; // n , m , S , T 点，边，源点，汇点

bool vis[MAXN];

int head[MAXN];

Node pre[MAXN];

Edge edge[ * MAXM];

void init() {

    ecnt = ;

    memset(edge, , sizeof(edge));

    memset(head, -, sizeof(head));

}

void addEdge(int u, int v, int w) {

    edge[ecnt].v = v;

    edge[ecnt].w = w;

    edge[ecnt].nxt = head[u];

    head[u] = ecnt++;

}

bool bfs(int s, int t) {

    queue <int> que;

    memset(vis, , sizeof(vis));

    memset(pre, -, sizeof(pre));

    pre[s].v = s;

    vis[s] = true;

    que.push(s);

    while(!que.empty()) {

        int u = que.front();

        que.pop();

        for(int i = head[u]; i + ; i = edge[i].nxt) {

            int v = edge[i].v;

            if(!vis[v] && edge[i].w) {

                pre[v].v = u;

                pre[v].id = i;

                vis[v] = true;

                if(v == t)

                    return true;

                que.push(v);

            }

        }

    }

    return false;

}

int EK(int s, int t) {

    int ans = ;

    while(bfs(s, t)) {

        int mi = MAX_INT;

        for(int i = t; i != s; i = pre[i].v) {

            mi = min(mi, edge[pre[i].id].w);

        }

        for(int i = t; i != s; i = pre[i].v) {

            edge[pre[i].id].w -= mi;

            edge[pre[i].id ^ ].w += mi; //异或1的用处是 偶数+1， 奇数-1 （两条正反向边是相邻的

        }

        ans += mi;

    }

    return ans;

}

int main() {

    freopen("1.txt","r", stdin);

    init();

    ios::sync_with_stdio(false);

    cin >> n >> m >> S >> T;

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

        int u, v, w;

        cin >> u >> v >> w;

        addEdge(u, v, w);

        addEdge(v, u, );

    }

    // 调用

    cout << EK(S, T) << "\n";

}

// 加边