#include "bits/stdc++.h"

// Begin {{{
using namespace std;
#define all(x) x.begin(), x.end()
#define rep(i, n) for (i64 i = 0, i##_limit = (n); i < i##_limit; ++i)
#define reps(i, b, e) for (i64 i = (b), i##_limit = (e); i <= i##_limit; ++i)
#define repr(i, b, e) for (i64 i = (b), i##_limit = (e); i >= i##_limit; --i)
#define var(Type, ...) Type __VA_ARGS__; input(__VA_ARGS__)
using i64 = int_fast64_t;
using pii = pair<i64, i64>;
template <class T> using MaxHeap = priority_queue<T>;
template <class T> using MinHeap = priority_queue<T, vector<T>, greater<>>;
template <class A, class B> inline bool chmax(A &a, const B &b) { return b > a && (a = b, true); }
template <class A, class B> inline bool chmin(A &a, const B &b) { return b < a && (a = b, true); }
inline i64 sigma(i64 n) { return n * (1 + n) >> 1; }
inline i64 updiv(i64 n, i64 d) { return (n + d - 1) / d; }
constexpr int INF = 0x3f3f3f3f;
constexpr i64 LINF = 0x3f3f3f3f3f3f3f3fLL;
#ifndef DEBUG
#define dump(...)
#endif

inline void input() {}
template <class Head, class... Tail>
inline void input(Head&& head, Tail&&... tail) {
    cin >> head;
    input(forward<Tail>(tail)...);
}

inline void outs() { cout << "\n"; }
template <class Head, class... Tail>
inline void outs(Head&& head, Tail&&... tail) {
    cout << head << (sizeof...(tail) ? " " : "");
    outs(forward<Tail>(tail)...);
}

template <class T>
inline void outs(vector<T> &vec) { for (auto &e : vec) cout << e << " \n"[&e == &vec.back()]; }

template <class T>
inline void outs(vector<vector<T>> &df) { for (auto &vec : df) outs(vec); }

inline void outl() { cout << "\n"; }
template <class Head, class... Tail>
inline void outl(Head&& head, Tail&&... tail) {
    cout << head << (sizeof...(tail) ? "\n" : "");
    outl(forward<Tail>(tail)...);
}

template <class T>
inline void outl(vector<T> &vec) { for (auto &e : vec) cout << e << "\n"; }

inline void outn() {}
template <class Head, class... Tail>
inline void outn(Head&& head, Tail&&... tail) {
    cout << head;
    outn(forward<Tail>(tail)...);
}

template <class T>
inline void outn(vector<T> &vec) { for (auto &e : vec) cout << e; }

template <class T>
inline vector<T> make_v(const T &initvalue, size_t sz) {
    return vector<T>(sz, initvalue);
}

template <class T, class... Args>
inline auto make_v(const T &initvalue, size_t sz, Args... args) {
    return vector<decltype(make_v<T>(initvalue, args...))>(sz, make_v<T>(initvalue, args...));
}
// }}} End

size_t N, M;
auto g = make_v(false, 60, 60);
vector<bool> seen;

void dfs(size_t now_node) {
    seen[now_node] = true;
    for (size_t next_node = 0; next_node < N; ++next_node) {
        if (g[now_node][next_node] && !seen[next_node]) {
            dfs(next_node);
        }
    }
}

signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> N >> M;

    vector<size_t> a(M), b(M);
    for (size_t i = 0; i < M; ++i) {
        cin >> a[i] >> b[i];
        a[i]--, b[i]--;
        g[a[i]][b[i]] = g[b[i]][a[i]] = true;
    }

    size_t res = 0;
    for (size_t i = 0; i < M; ++i) {
        g[a[i]][b[i]] = g[b[i]][a[i]] = false;
        seen.assign(60, false);
        dfs(0);
        for (size_t node = 0; node < N; ++node) {
            if (!seen[node]) {
                res++;
                break;
            }
        }

        g[a[i]][b[i]] = g[b[i]][a[i]] = true;
    }

    cout << res << "\n";

    return 0;
}


Measured memory_bytes: 256