#include <bits/stdc++.h>
#define ll long long
#define int ll
#define enl putchar('\n')
#define all(x) (x).begin(),(x).end()
#define debug(x) printf(" "#x":%d\n",x);
using namespace std;
const int N = 100 + 5, M = 5000;
const int inf = 0x3f3f3f3f;
const ll INF = 0x3f3f3f3f3f3f3f3f;
const int mod = 998244353;
typedef pair<int, int> pii;
char buf[1 << 21], * p1 = buf, * p2 = buf, obuf[1 << 21], * o = obuf, of[35];
#define gc()(p1==p2&&(p2=(p1=buf)+fread(buf,1,1<<21,stdin),p1==p2)?EOF:*p1++)
inline ll qpow(ll a, ll n) { ll res = 1; while (n) { if (n & 1)res = res * a % mod; n >>= 1; a = a * a % mod; }return res; }
template <class T = int>inline T read() { T s = 0, f = 1; char c = gc(); for (; !isdigit(c); c = gc())if (c == '-')f = -1; for (; isdigit(c); c = gc())s = s * 10 + c - '0'; return s * f; }
inline void read(int* a, int n) { for (int i = 1; i <= n; ++i)a[i] = read(); }
inline int inal(char* s) { int n = 0; for (s[0] = gc(); !isalpha(s[0]); s[0] = gc()); for (; isalpha(s[n]); s[++n] = gc()); return s[n] = 0, n; }
inline int indi(char* s) { int n = 0; for (s[0] = gc(); !isdigit(s[0]); s[0] = gc()); for (; isdigit(s[n]); s[++n] = gc()); return s[n] = 0, n; }
inline void outd(auto* a, int n) { for (int i = 1; i <= n; ++i)printf("%d ", a[i]); enl; }
int n, m, S, T, totnode;
int head[N], tot, cur[N], gap[N], ht[N], ex[N];  // 高度; 超额流; gap 优化 gap[i] 为高度为 i 的节点的数量
struct node {
    int to, nxt;
    ll val;
}e[M << 1];
inline void add(int u, int v, ll w) {
    e[tot] = node {v, head[u], w};
    head[u] = tot++;

    e[tot] = node {u, head[v], 0};
    head[v] = tot++;
}

stack<int> B[N];  // 桶 B[i] 中记录所有 ht[v]==i 的v
int level = 0;    // 溢出节点的最高高度
int push(int u) {      // 尽可能通过能够推送的边推送超额流
    bool init = u == S;  // 是否在初始化
    for (int i = head[u]; ~i; i = e[i].nxt) {
        const int& v = e[i].to, & w = e[i].val;
        if (!w || init == false && ht[u] != ht[v] + 1 ||
            ht[v] == inf)  // 初始化时不考虑高度差为1
            continue;
        int k = init ? w : min(w, ex[u]);
        // 取到剩余容量和超额流的最小值，初始化时可以使源的溢出量为负数。
        if (v != S && v != T && !ex[v]) B[ht[v]].push(v), level = max(level, ht[v]);
        ex[u] -= k, ex[v] += k, e[i].val -= k, e[i ^ 1].val += k;  // push
        if (!ex[u]) return 0;  // 如果已经推送完就返回
    }
    return 1;
}

void relabel(int u) {  // 重贴标签（高度）
    ht[u] = inf;
    for (int i = head[u]; ~i; i = e[i].nxt)
        if (e[i].val) ht[u] = min(ht[u], ht[e[i].to]);
    if (++ht[u] < totnode) {  // 只处理高度小于 n 的节点
        B[ht[u]].push(u);
        level = max(level, ht[u]);
        ++gap[ht[u]];  // 新的高度，更新 gap
    }
}

bool bfs() {
    memset(ht, 0x3f, sizeof(ht));
    queue<int> q;
    q.push(T), ht[T] = 0;
    while (q.size()) {  // 反向 BFS, 遇到没有访问过的结点就入队
        int u = q.front();
        q.pop();
        for (int i = head[u]; ~i; i = e[i].nxt) {
            const int& v = e[i].to;
            if (e[i ^ 1].val && ht[v] > ht[u] + 1) ht[v] = ht[u] + 1, q.push(v);
        }
    }
    return ht[S] != inf;  // 如果图不连通，返回 0
}

// 选出当前高度最大的节点之一, 如果已经没有溢出节点返回 0
int select() {
    while (B[level].size() == 0 && level > -1) level--;
    return level == -1 ? 0 : B[level].top();
}
int HLPP() {                  // 返回最大流
    if (!bfs()) return 0;  // 图不连通
    memset(gap, 0, sizeof(gap));
    for (int i = 1; i <= totnode; i++)
        if (ht[i] != inf) gap[ht[i]]++;  // 初始化 gap
    ht[S] = totnode;
    push(S);  // 初始化预流
    int u;
    while ((u = select())) {
        B[level].pop();
        if (push(u)) {  // 仍然溢出
            if (!--gap[ht[u]])
                for (int i = 1; i <= totnode; i++)
                    if (i != S && i != T && ht[i] > ht[u] && ht[i] < totnode + 1)
                        ht[i] = totnode + 1;  // 这里重贴成 n+1 的节点都不是溢出节点
            relabel(u);
        }
    }
    return ex[T];
}
void solve() {
    n = read(), m = read(), S = read(), T = read();
    totnode = n;
    memset(head, -1, sizeof(head));
    for (int i = 1; i <= m; ++i) {
        int u = read(), v = read(), w = read();
        add(u, v, w);
    }
    printf("%lld\n", HLPP());
}
signed main(signed argc, char const* argv[]) {
    clock_t c1 = clock();
#ifdef LOCAL
    freopen("in.in", "r", stdin);
    freopen("out.out", "w", stdout);
#endif
    //=============================================================
    int TxT = 1;
    // TxT = read();
    while (TxT--)
        solve();
    //=============================================================
#ifdef LOCAL
    end :
    cerr << "Time Used:" << clock() - c1 << "ms" << endl;
#endif
    return 0;
}