// clang-format off
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define main signed main()
#define loop(i, a, n) for (int i = (a); i < (n); i++)
#define rep(i, n) loop(i, 0, n)
#define all(v) (v).begin(), (v).end()
#define rall(v) (v).rbegin(), (v).rend()
#define prec(n) fixed << setprecision(n)
constexpr int INF = sizeof(int) == sizeof(long long) ? 1000000000000000000LL : 1000000000;
constexpr int MOD = 1000000007;
constexpr double PI = 3.14159265358979;
template<typename A, typename B> bool cmin(A &a, const B &b) { return a > b ? (a = b, true) : false; }
template<typename A, typename B> bool cmax(A &a, const B &b) { return a < b ? (a = b, true) : false; }
bool odd(const int &n) { return n & 1; }
bool even(const int &n) { return ~n & 1; }
template<typename T> int len(const T &v) { return v.size(); }
template<typename T = int> T in() { T x; cin >> x; return x; }
template<typename T = int> T in(T &&x) { T z(forward<T>(x)); cin >> z; return z; }
template<typename T> istream &operator>>(istream &is, vector<T> &v) { for (T &x : v) is >> x; return is; }
template<typename A, typename B> istream &operator>>(istream &is, pair<A, B> &p) { return is >> p.first >> p.second; }
template<typename T> ostream &operator<<(ostream &os, const vector<vector<T>> &v) { int n = v.size(); rep(i, n) os << v[i] << (i == n - 1 ? "" : "\n"); return os; }
template<typename T> ostream &operator<<(ostream &os, const vector<T> &v) { int n = v.size(); rep(i, n) os << v[i] << (i == n - 1 ? "" : " "); return os; }
template<typename A, typename B> ostream &operator<<(ostream &os, const pair<A, B> &p) { return os << p.first << ' ' << p.second; }
template<typename Head, typename Value> auto vectors(const Head &head, const Value &v) { return vector<Value>(head, v); }
template<typename Head, typename... Tail> auto vectors(Head x, Tail... tail) { auto inner = vectors(tail...); return vector<decltype(inner)>(x, inner); }
// clang-format on

using Weight = int;
struct Edge {
  int src, dst;
  Weight weight;
  Edge(const int &s = 0, const int &d = 0, const Weight &w = 0) : src(s), dst(d), weight(w) {}
};

using Edges = vector<Edge>;
using Array = vector<Weight>;
using Matrix = vector<Array>;

class Graph {
  vector<Edges> g;
  using iterator = vector<Edges>::iterator;
  using const_iterator = vector<Edges>::const_iterator;

public:
  Graph(const int &size = 0) : g(size) {}
  size_t size() const { return g.size(); }
  const Edges &operator[](const int &i) const { return g[i]; }
  Edges &operator[](const int &i) { return g[i]; }
  void addArc(const int &src, const int &dst, const Weight &w = 1) { g[src].emplace_back(src, dst, w); }
  void addEdge(const int &node1, const int &node2, const Weight &w = 1) {
    addArc(node1, node2, w);
    addArc(node2, node1, w);
  }
  iterator begin() { return g.begin(); }
  const_iterator begin() const { return g.begin(); }
  iterator end() { return g.end(); }
  const_iterator end() const { return g.end(); }
};

int ChuLiuEdmonds(const Graph &g, const int &r, int n = -1) {
  if (n == -1) n = g.size();
  vector<Edge> mins(n, {-1, -1, INF});
  for (auto &es : g) {
    for (auto &e : es) {
      if (mins[e.dst].weight > e.weight) mins[e.dst] = e;
    }
  }
  mins[r] = {-1, -1, 0};

  vector<int> group(n, 0), isCycle(n, false), used(n, false);
  int groupId = 0;

  rep(i, n) {
    if (used[i]) continue;
    vector<int> chain;
    int cursor = i;
    while (cursor != -1 && not used[cursor]) {
      used[cursor] = true;
      chain.emplace_back(cursor);
      cursor = mins[cursor].src;
    }
    if (cursor != -1) {
      bool inCycle = false;
      for (auto &v : chain) {
        group[v] = groupId;
        if (v == cursor) {
          isCycle[groupId] = true;
          inCycle = true;
        }
        if (not inCycle) groupId++;
      }
      if (inCycle) groupId++;
    } else {
      for (auto &v : chain) group[v] = groupId++;
    }
  }

  if (groupId == n) {
    int allCost = 0;
    rep(i, n) allCost += mins[i].weight;
    return allCost;
  }

  int cyclesCost = 0;
  rep(i, n) {
    if (i == r || not isCycle[group[i]]) continue;
    cyclesCost += mins[i].weight;
  }

  Graph h(n);
  for (auto &es : g) {
    for (auto &e : es) {
      if (group[e.src] == group[e.dst]) continue;
      h.addArc(group[e.src], group[e.dst], e.weight - mins[e.dst].weight * isCycle[group[e.dst]]);
    }
  }

  return cyclesCost + ChuLiuEdmonds(h, group[r], groupId);
}

main {
  int n, m, r;
  cin >> n >> m >> r;
  Graph g(n);
  while (m--) {
    int s, t, w;
    cin >> s >> t >> w;
    g.addArc(s, t, w);
  }
  cout << ChuLiuEdmonds(g, r) << endl;
}



Measured memory_bytes: 4072