#line 1 "template/template.hpp"
#include <bits/stdc++.h>

#if __has_include(<atcoder/all>)
#include <atcoder/all>

#endif

using namespace std;

using int64 = long long;

const int64 infll = (1LL << 62) - 1;
const int inf = (1 << 30) - 1;

struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;

template <typename T1, typename T2>
ostream& operator<<(ostream& os, const pair<T1, T2>& p) {
  os << p.first << " " << p.second;
  return os;
}

template <typename T1, typename T2>
istream& operator>>(istream& is, pair<T1, T2>& p) {
  is >> p.first >> p.second;
  return is;
}

template <typename T>
ostream& operator<<(ostream& os, const vector<T>& v) {
  for (size_t i = 0; i < v.size(); i++) {
    os << v[i] << (i + 1 != v.size() ? " " : "");
  }
  return os;
}

template <typename T>
istream& operator>>(istream& is, vector<T>& v) {
  for (T& in : v) is >> in;
  return is;
}

template <typename T1, typename T2>
bool chmax(T1& a, T2 b) {
  return a < b && (a = b, true);
}

template <typename T1, typename T2>
bool chmin(T1& a, T2 b) {
  return a > b && (a = b, true);
}

template <typename T = int64>
vector<T> make_v(size_t a) {
  return vector<T>(a);
}

template <typename T, typename... Ts>
auto make_v(size_t a, Ts... ts) {
  return vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}

template <typename T, typename V>
enable_if_t<is_class_v<T> == 0> fill_v(T& t, const V& v) {
  t = v;
}

template <typename T, typename V>
enable_if_t<is_class_v<T> != 0> fill_v(T& t, const V& v) {
  for (auto& e : t) fill_v(e, v);
}

template <typename F>
struct FixPoint : F {
  explicit FixPoint(F&& f) : F(std::forward<F>(f)) {}

  template <typename... Args>
  decltype(auto) operator()(Args&&... args) const {
    return F::operator()(*this, std::forward<Args>(args)...);
  }
};

template <typename F>
decltype(auto) MFP(F&& f) {
  return FixPoint<F>{std::forward<F>(f)};
}

#line 2 "graph/flow/dinic-capacity-scaling.hpp"

#include <algorithm>
#include <iostream>
#include <limits>
#include <queue>
#include <type_traits>
#include <vector>

/**
 * @brief Dinic Capacity Scaling(最大流)
 *
 */
template <typename flow_t>
struct DinicCapacityScaling {
  static_assert(std::is_integral<flow_t>::value,
                "template parameter flow_t must be integral type");

  const flow_t INF;

  struct edge {
    int to;
    flow_t cap;
    int rev;
    bool isrev;
    int idx;
  };

  std::vector<std::vector<edge> > graph;
  std::vector<int> min_cost, iter;
  flow_t max_cap;

  explicit DinicCapacityScaling(int V)
      : INF(std::numeric_limits<flow_t>::max()), graph(V), max_cap(0) {}

  void add_edge(int from, int to, flow_t cap, int idx = -1) {
    max_cap = std::max(max_cap, cap);
    graph[from].emplace_back(
        (edge){to, cap, (int)graph[to].size(), false, idx});
    graph[to].emplace_back(
        (edge){from, 0, (int)graph[from].size() - 1, true, idx});
  }

  bool build_augment_path(int s, int t, const flow_t& base) {
    min_cost.assign(graph.size(), -1);
    std::queue<int> que;
    min_cost[s] = 0;
    que.push(s);
    while (!que.empty() && min_cost[t] == -1) {
      int p = que.front();
      que.pop();
      for (auto& e : graph[p]) {
        if (e.cap >= base && min_cost[e.to] == -1) {
          min_cost[e.to] = min_cost[p] + 1;
          que.push(e.to);
        }
      }
    }
    return min_cost[t] != -1;
  }

  flow_t find_augment_path(int idx, const int t, flow_t base, flow_t flow) {
    if (idx == t) return flow;
    flow_t sum = 0;
    for (int& i = iter[idx]; i < (int)graph[idx].size(); i++) {
      edge& e = graph[idx][i];
      if (e.cap >= base && min_cost[idx] < min_cost[e.to]) {
        flow_t d =
            find_augment_path(e.to, t, base, std::min(flow - sum, e.cap));
        if (d > 0) {
          e.cap -= d;
          graph[e.to][e.rev].cap += d;
          sum += d;
          if (flow - sum < base) break;
        }
      }
    }
    return sum;
  }

  flow_t max_flow(int s, int t) {
    if (max_cap == flow_t(0)) return flow_t(0);
    flow_t flow = 0;
    for (int i = 63 - __builtin_clzll(max_cap); i >= 0; i--) {
      flow_t now = flow_t(1) << i;
      while (build_augment_path(s, t, now)) {
        iter.assign(graph.size(), 0);
        flow += find_augment_path(s, t, now, INF);
      }
    }
    return flow;
  }

  void output() {
    for (int i = 0; i < graph.size(); i++) {
      for (auto& e : graph[i]) {
        if (e.isrev) continue;
        auto& rev_e = graph[e.to][e.rev];
        std::cout << i << "->" << e.to << " (flow: " << rev_e.cap << "/"
                  << e.cap + rev_e.cap << ")" << std::endl;
      }
    }
  }
};



int main() {
  int N, M, S, T;
  cin >> N >> M >> S >> T;
  DinicCapacityScaling< int64 > g(N);
  for (int i = 0; i < M; i++) {
    int a, b, c;
    cin >> a >> b >> c;
    --a, --b;
    g.add_edge(a, b, c);
  }
  cout << g.max_flow(S - 1, T - 1) << endl;
}