#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx2")

// 数値型
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using P = pair<int,int>;
using Pll = pair<ll, ll>;
using Pli = pair<ll, int>;
using Pil = pair<int, ll>;

// vector関連
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
template<typename T>
using vc = vector<T>;
template<typename T>
using vvc = vector<vc<T>>;
template<typename T>
using vvvc = vector<vvc<T>>;
template<typename T>
using vvvvc = vector<vvvc<T>>;

// priority_queue
template<typename T>
using pq = priority_queue<T>;
template<typename T>
using pqg = priority_queue<T, vc<T>, greater<T>>;

#define rep(i, n) for(int i = 0; i < (int)(n); i++)
#define FOR(i, a, b) for(int i = a; i < (int)(b); i++)
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define MIN(vec) *min_element(vec)
#define MAX(vec) *max_element(vec)
#define next_perm(vec) next_permutation((vec).begin(), (vec).end())
#define UNIQUE(vec) vec.erase(unique(vec.begin(), vec.end()), vec.end())
#define el "\n"
#define Yes cout << "Yes" << el
#define No cout << "No" << el
#define YES cout << "YES" << el
#define NO cout << "NO" << el
#define EPS 1e-8
#define Equal(a, b) (fabs((a)-(b)) < EPS) 
#define dbg(x) cerr << #x << "=" << x << el 

// 定数
const string abc = "abcdefghijklmnopqrstuvwxyz";
const string ABC = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
constexpr int INF = 1001001001;
constexpr ll LINF = 1001001001001001001ll;
constexpr int DX[] = {1, 0, -1, 0};
constexpr int DY[] = {0, 1, 0, -1};
constexpr int DX8[] = {1, 0, -1, 0, 1, 1, -1, -1};
constexpr int DY8[] = {0, 1, 0, -1, 1, -1, 1, -1};

template<typename T1, typename T2>
ostream &operator<< (ostream &os, pair<T1, T2> p) {
    os << "{" << p.first << "," << p.second << "}";
    return os;
}
template<typename T>
ostream &operator<< (ostream &os, vc<T> &vec) {
    int sz = vec.size();
    rep(i, sz){
        os << vec[i] << (i==sz-1?"":" ");
    }
    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>
istream &operator>> (istream &is, vc<T> &vec) {
    int sz = vec.size();
    rep(i, sz) { is >> vec[i]; }
    return is;
}
/// @brief aとｂの最大値をaに格納。更新があったかbool値を返す
/// @tparam T1 
/// @tparam T2 
/// @param a 
/// @param b 
/// @return bool
template<typename T1, typename T2>
inline bool chmax(T1 &a, T2 b){
    bool ret = a<b;
    if(ret) a = b;
    return ret;
}

/// @brief aとｂの最小値をaに格納。更新があったかbool値を返す
/// @tparam T1 
/// @tparam T2 
/// @param a 
/// @param b 
/// @return bool
template<typename T1, typename T2>
inline bool chmin(T1 &a, T2 b){
    bool ret = a>b;
    if(ret) {a = b;}
    return ret;
}

inline void YesNo(bool flag){
    if(flag) {Yes;}
    else {No;}
    return;
}

inline void YESNO(bool flag){
    if(flag) {YES;}
    else {NO;}
    return;
}

inline bool outof(ll x, ll xlim){
    return (x<0 || x>=xlim);
}

template<typename T>
inline T sqnorm(T x, T y){
    return x*x+y*y;
}

/// @brief char->int
/// @param c 
/// @return int
inline int ctoi(char c){
    return c-'0';
}

/// @brief xを素因数分解
/// @param x 
/// @return vector<Pli>, 素因数の昇順に {p, cnt}
vector<Pli> prime_fact(ll x){
    vector<Pli> ret;
    for(ll i=2; i*i<=x; i++){
        if(x%i == 0){
            ret.emplace_back(i, 0);
            while(x%i == 0){
                ret.back().second++;
                x /= i;
            }
        }
    }
    if(x != 1) ret.emplace_back(x, 1);
    return ret;
}

/// @brief xの約数列挙
/// @param x 
/// @return vll, 約数の昇順
vll divisor_enum(ll x){
    vector<ll> ret;
    for(ll i=1; i*i<=x; i++){
        if(x%i == 0){
            ret.push_back(x/i);
            ret.push_back(i);
        }
    }
    sort(all(ret));
    UNIQUE(ret);
    return ret;
}

/// @brief 繰り返し二乗法。
/// @tparam T 
/// @param x 
/// @param k 
/// @param op 
/// @param e 
/// @return 
template<typename T>
T pow_t(T x, ll k, T (*op)(T, T), T (*e)()){
    T ret = e();
    while(k){
        if(k&1) ret = op(ret, x);
        x = op(x, x);
        k >>= 1;
    }
    return ret;
}

ll powll(ll x, ll k){
    return pow_t<ll>(x, k, [](ll a, ll b) -> ll{return a*b;}, []() -> ll{return 1;});
}

inline int pop_cnt(ll x) { return __builtin_popcountll(x); }
inline int top_bit(ll x) { return (x==0?-1:63-__builtin_clzll(x));}

void main2();

int main(){
    ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    main2();
}
template< typename flow_t >
struct PushRelabel {
  const flow_t INF;

  struct edge {
    int to;
    flow_t cap;
    int rev;
    bool isrev;
    int idx;
  };
  vector< vector< edge > > graph;
  vector< flow_t > ex;
  int relabels, high;
  vector< int > cnt, h;
  vector< vector< int > > hs;

  PushRelabel(int V) : graph(V), INF(numeric_limits< flow_t >::max()), hs(V + 1), high(0) {}


  void add_edge(int from, int to, flow_t cap, int idx = -1) {
    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});
  }

  void update_height(int idx, int nxt_height) {
    ++relabels;
    if(h[idx] != graph.size() + 1) {
      --cnt[h[idx]];
    }
    h[idx] = nxt_height;
    if(h[idx] != graph.size() + 1) {
      high = nxt_height;
      ++cnt[nxt_height];
      if(ex[idx] > 0) hs[nxt_height].emplace_back(idx);
    }
  }

  void global_relabel(int idx) {
    for(int i = 0; i <= high; i++) hs[i].clear();
    relabels = 0;
    high = 0;
    h.assign(graph.size(), graph.size() + 1);
    cnt.assign(graph.size(), 0);
    queue< int > que;
    que.emplace(idx);
    h[idx] = 0;
    while(que.size()) {
      int p = que.front();
      que.pop();
      for(auto &e : graph[p]) {
        if(h[e.to] == graph.size() + 1 && graph[e.to][e.rev].cap > 0) {
          que.emplace(e.to);
          high = h[p] + 1;
          update_height(e.to, high);
        }
      }
    }
  }


  void push(int idx, edge &e) {
    if(h[e.to] == graph.size() + 1) return;
    if(ex[e.to] == 0) {
      hs[h[e.to]].emplace_back(e.to);
    }
    flow_t df = min(ex[idx], e.cap);
    e.cap -= df;
    graph[e.to][e.rev].cap += df;
    ex[idx] -= df;
    ex[e.to] += df;
  }

  void discharge(int idx) {
    int next_height = (int) graph.size() + 1;
    for(auto &&e : graph[idx]) {
      if(e.cap > 0) {
        if(h[idx] == h[e.to] + 1) {
          push(idx, e);
          if(ex[idx] <= 0) return;
        } else {
          next_height = min(next_height, h[e.to] + 1);
        }
      }
    }
    if(cnt[h[idx]] > 1) {
      update_height(idx, next_height);
    } else {
      for(; high >= h[idx]; hs[high--].clear()) {
        for(int j : hs[high]) update_height(j, graph.size() + 1);
      }
    }
  }

  flow_t max_flow(int s, int t) {
    ex.assign(graph.size(), 0);
    ex[s] = INF;
    ex[t] = -INF;
    global_relabel(t);
    for(auto &e : graph[s]) push(s, e);
    for(; high >= 0; high--) {
      while(!hs[high].empty()) {
        int idx = hs[high].back();
        hs[high].pop_back();
        discharge(idx);
        if(relabels >= graph.size() * 4) global_relabel(t);
      }
    }
    return ex[t] + INF;
  }

  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];
        cout << i << "->" << e.to << " (flow: " << rev_e.cap << "/" << e.cap + rev_e.cap << ")" << endl;
      }
    }
  }
};
// https://ei1333.github.io/luzhiled/snippets/graph/push-relabel.html

void main2(){
    int n, m, s, t;
    cin >> n >> m >> s >> t;
    PushRelabel<int> mf(n);
    rep(i, m) {
        int u, v, c;
        cin >> u >> v >> c;
        mf.add_edge(u-1, v-1, c);
    }
    cout << mf.max_flow(s-1, t-1) << el;
}