#include <algorithm>
#include <array>
#include <bitset>
#include <complex>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <set>
#include <stack>
#include <unordered_map>
#include <unordered_set>
#include <queue>

using namespace std;

struct Initializer {
  Initializer() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(15);
  }
} initializer;

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

template<typename T> ostream& operator<<(ostream &s, const vector<T> &v) {
  for (const T &t : v) s << t << endl;
  return s;
}

template<typename Edge> struct FullEdge : public Edge {
  int from;

  FullEdge() = default;

  FullEdge(const int from, const Edge& edge) : Edge(edge), from(from) {}
};

struct Edge {
  using CostType = int;
  const static int cost = 1;
  int to;
  Edge(int to = -1) : to(to) {}
  bool isNone() const {return to == -1;}
};

istream& operator>>(istream &s, FullEdge<Edge> &edge) {
  s >> edge.from >> edge.to;
  return s;
}

ostream& operator<<(ostream &s, const FullEdge<Edge> &edge) {
  s << '(' << edge.from << ',' << edge.to << ')';
  return s;
}

template<typename Cost> struct WeightedEdge : public Edge {
  using CostType = Cost;
  Cost cost;
  WeightedEdge(int to = -1, Cost cost = 0) : Edge(to), cost(cost) {}
};

template<typename Cost> istream& operator>>(istream &s, FullEdge<WeightedEdge<Cost>> &edge) {
  s >> edge.from >> edge.to >> edge.cost;
  return s;
}

template<typename Cost> ostream& operator<<(ostream &s, const FullEdge<WeightedEdge<Cost>> &edge) {
  s << '(' << edge.from << ',' << edge.to << ',' << edge.cost << ')';
  return s;
}

template<typename Capacity> struct ResidualEdge : public Edge {
  using CapacityType = Capacity;
  Capacity cap;
  int rev;
  ResidualEdge(int to = -1, Capacity cap = 0) : Edge(to), cap(cap) {}
  ResidualEdge reverse(int from) const {return ResidualEdge(from, 0);}
};

template<typename Capacity, typename Cost> struct WeightedResidualEdge : public ResidualEdge<Capacity> {
  Cost cost;
  WeightedResidualEdge(int to = -1, Capacity cap = 0, Cost cost = 0) : ResidualEdge<Capacity>(to, cap), cost(cost) {}
  WeightedResidualEdge reverse(int from) const {return WeightedResidualEdge(from, 0, -cost);}
};

template<typename Edge> class Graph {
public:
  using EdgeType = Edge;
  virtual int size() const = 0;
  template<typename... Args> void addEdge(int from, int to, Args...) {
    (void)from;
    (void)to;
  }
  template<typename... Args> void addUndirectedEdge(int from, int to, Args...) {
    (void)from;
    (void)to;
  }

  vector<FullEdge<Edge>> getAllEdges() const {
    vector<FullEdge<Edge>> res;
    for (int i = 0; i < size(); ++i) {
      for (const auto& edge : getEdges(i)) {
        res.emplace_back(i, edge);
      }
    }
    return res;
  }

  virtual vector<Edge> getEdges(int from) const = 0;
  virtual Edge getEdge(int from, int to) const = 0;
  virtual bool hasEdge(int from, int to) const = 0;

  int getDegree(int v) const {
    return getEdges(v).size();
  }

  vector<int> getIndegree() const {
    vector<int> degree(size());
    for (const auto& edge : getAllEdges()) ++degree[edge.second.to];
    return degree;
  }
};

template<typename Graph> Graph readGraph(int n = -1, int m = -1, bool undirected = true, bool one_origin = true) {
  if (n == -1) cin >> n >> m;
  Graph graph(n);
  for (int i = 0; i < m; ++i) {
    FullEdge<typename Graph::EdgeType> edge;
    cin >> edge;
    if (one_origin) {
      --edge.from;
      --edge.to;
    }
    if (undirected) graph.addUndirectedEdge(edge);
    else graph.addEdge(edge);
  }
  return graph;
}

template<typename Edge> class AdjacencyList : public Graph<Edge> {
protected:
  vector<vector<Edge>> graph;

public:
  using EdgeType = Edge;

  AdjacencyList(int n) : graph(n) {}

  int size() const {
    return graph.size();
  }
  
  template<typename... Args> void addEdge(int from, int to, Args... args) {
    graph[from].emplace_back(to, args...);
  }

  void addEdge(const FullEdge<Edge>& edge) {
    graph[edge.from].emplace_back(edge);
  }

  template<typename... Args> void addUndirectedEdge(int from, int to, Args... args) {
    addEdge(from, to, args...);
    addEdge(to, from, args...);
  }

  void addUndirectedEdge(FullEdge<Edge> edge) {
    graph[edge.from].emplace_back(edge);
    swap(edge.from, edge.to);
    graph[edge.from].emplace_back(edge);
  }

  vector<Edge> getEdges(int from) const {
    return graph[from];
  }

  Edge getEdge(int from, int to) const {
    Edge res;
    for (const auto& edge : graph[from]) {
      if (edge.to == to) res = edge;
    }
    return res;
  }

  bool hasEdge(int from, int to) const {
    for (const auto& edge : graph[from]) {
      if (edge.to == to) return true;
    }
    return false;
  }

  vector<Edge>& operator[](int v) {
    return graph[v];
  }
};

template<typename T> bool chmin(T& a, T b) {return a > b ? a = b, true : false;}

template<typename T> bool chmax(T& a, T b) {return a < b ? a = b, true : false;}

template<typename Graph> class LowLink {
private:
  using Edge = typename Graph::EdgeType;

  const Graph graph;
  vector<bool> visited;
  vector<int> ord, low;
  int k;

  void dfs(int pos, int par = -1) {
    visited[pos] = true;
    low[pos] = ord[pos] = k;
    ++k;
    for (const auto& edge : graph.getEdges(pos)) {
      int next = edge.to;
      if (!visited[next]) {
        dfs(next, pos);
        chmin(low[pos], low[next]);
      } else if (next != par) {
        chmin(low[pos], ord[next]);
      }
    }
  }

public:
  LowLink(const Graph& graph) : graph(graph), visited(graph.size()), ord(graph.size()), low(graph.size()), k(0) {
    for (int i = 0; i < int(graph.size()); ++i) {
      if (!visited[i]) dfs(i);
    }
  }

  vector<FullEdge<Edge>> bridge() {
    vector<FullEdge<Edge>> res;
    for (const auto& edge : graph.getAllEdges()) {
      if (ord[edge.from] < low[edge.to]) res.emplace_back(edge);
    }
    return res;
  }
};

int main() {
  using Graph = AdjacencyList<Edge>;
  auto graph = readGraph<Graph>();
  cout << LowLink<Graph>(graph).bridge().size() << endl;
}



Measured memory_bytes: 256