#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <stack>
#include <cmath>
#include <deque>
#include <queue>
#include <map>
#include <bitset>
#include <set>
#include <list>
#include <unordered_map>
#include <unordered_set>
#include <sstream>
#include <numeric>
#include <climits>
#include <utility>
#include <iomanip>
#include <cassert>

using namespace std;

using ll = long long;
using ii = pair<int, int>;
using iii = pair<int, ii>;
template <class T>
using vv = vector<vector<T>>;

#define rep(i, b) for (int i = 0; i < int(b); ++i)
#define reps(i, a, b) for (int i = int(a); i < int(b); ++i)
#define rrep(i, b) for (int i = int(b) - 1; i >= 0; --i)
#define rreps(i, a, b) for (int i = int(b) - 1; i >= a; --i)
#define repe(i, b) for (int i = 0; i <= int(b); ++i)
#define repse(i, a, b) for (int i = int(a); i <= int(b); ++i)
#define rrepe(i, b) for (int i = int(b); i >= 0; --i)
#define rrepse(i, a, b) for (int i = int(b); i >= int(a); --i)

#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define sz(a) int(a.size())
#define mp(a, b) make_pair(a, b)

#define inf (INT_MAX / 2)
#define infl (LONG_MAX / 2)
#define infll (LLONG_MAX / 2)

#define X first
#define Y second
#define pb push_back
#define eb emplace_back

// tools for pair<int, int> & graph
template <class T, size_t M, size_t N>
class graph_delegate_t {
    T (&f)[M][N];

public:
    graph_delegate_t(T (&f)[M][N]) : f(f) {}
    T& operator[](const ii& s) { return f[s.first][s.second]; }
    const T& operator[](const ii& s) const { return f[s.first][s.second]; }
};
ii operator+(const ii& lhs, const ii& rhs) {
    return mp(lhs.first + rhs.first, lhs.second + rhs.second);
}

// clang-format off
template <class S, class T> ostream& operator<<(ostream& os, const pair<S, T>& t) { return os << "(" << t.first << "," << t.second << ")"; }
template <class T> ostream& operator<<(ostream& os, const vector<T>& t) { os << "{"; rep(i, t.size() - 1) { os << t[i] << ","; } if (!t.empty()) os << t.back(); os << "}"; return os; }
vector<string> __macro_split(const string& s) { vector<string> v; int d = 0, f = 0; string t; for (char c : s) { if (!d && c == ',') v.pb(t), t = ""; else t += c; if (c == '\"' || c == '\'') f ^= 1; if (!f && c == '(') ++d; if (!f && c == ')') --d; } v.pb(t); return v; }
void __args_output(vector<string>::iterator, vector<string>::iterator) { cerr << endl; }
template <typename T, typename... Args>
void __args_output(vector<string>::iterator it, vector<string>::iterator end, T a, Args... args) { cerr << it->substr((*it)[0] == ' ', it->length()) << " = " << a; if (++it != end) { cerr << ", "; } __args_output(it, end, args...); }
#define out(args...) { vector<string> __args = __macro_split(#args); __args_output(__args.begin(), __args.end(), args); }
// clang-format on

const int MAX_N = 50;

int n, m;
bool visited[MAX_N];
ii ed[MAX_N * MAX_N];
set<int> edges[MAX_N];

void dfs(int u) {
    if (visited[u]) return;
    visited[u] = true;
    for (auto v : edges[u]) {
        dfs(v);
    }
}

bool is_bridge() {
    rep(i, n) if (!visited[i]) return true;
    return false;
}

int main() {
    cin >> n >> m;
    rep(i, m) {
        int a, b;
        cin >> a >> b;
        --a, --b;
        ed[i].first = a, ed[i].second = b;
        edges[a].insert(b);
        edges[b].insert(a);
    }

    int res = 0;
    rep(i, m) {
        int a = ed[i].first, b = ed[i].second;
        edges[a].erase(b);
        edges[b].erase(a);
        dfs(0);
        if (is_bridge()) res++;
        fill_n(visited, n, false);
        edges[a].insert(b);
        edges[b].insert(a);
    }
    cout << res << endl;

    return 0;
}

Measured memory_bytes: 256