#include <bits/stdc++.h>
using namespace std;

#define NDEBUG
#include <cassert>


typedef long long ll;
typedef long double Double;
typedef unsigned long long ull;
typedef pair<int,int> ii;
typedef pair<ll,ll> llll;
typedef pair<double,double> dd;

typedef vector<int> vi;
typedef vector<vector<int>> vvi;
typedef vector<ii> vii;
typedef vector<vector<ii>> vvii;
typedef vector<ll> vll;
typedef vector<vector<ll>> vvll;
typedef vector<llll> vllll;
typedef vector<bool> vb;
typedef vector<string> vs;
typedef vector<double> vd;
typedef vector<long double> vD;

#define sz(a)  int((a).size())
#define pb  push_back
#define eb  emplace_back
#define FOR(var,from,to) for(int var=(from);var<=(to);++var)
#define rep(var,n)  for(int var=0;var<(n);++var)
#define rep1(var,n)  for(int var=1;var<=(n);++var)
#define repC2(vari,varj,n)  for(int vari=0;vari<(n)-1;++vari)for(int varj=vari+1;varj<(n);++varj)
#define repC3(vari,varj,vark,n)  for(int vari=0;vari<(n)-2;++vari)for(int varj=vari+1;varj<(n)-1;++varj)for(int vark=varj+1;vark<(n);++vark)
#define ALL(c)  (c).begin(),(c).end()
#define RALL(c)  (c).rbegin(),(c).rend()
#define tr(i,c)  for(auto i=(c).begin(); i!=(c).end(); ++i)
#define found(s,e)  ((s).find(e)!=(s).end())
#define mset(arr,val)  memset(arr,val,sizeof(arr))
#define mid(x,y) ((x)+((y)-(x))/2)
#define IN(x,a,b) ((a)<=(x)&&(x)<=(b))
#define cons make_pair
#define clamp(v,lo,hi) min(max(v,lo),hi)
#define ABS(x) max((x),-(x))

template<typename T1, typename T2> inline void amin(T1 & a, T2 const & b) { if (a>b) a=b; }
template<typename T1, typename T2> inline void amax(T1 & a, T2 const & b) { if (a<b) a=b; }
template<typename X, typename T> auto vectors(X x, T a) { return vector<T>(x, a); }
template<typename X, typename Y, typename Z, typename... Zs> auto vectors(X x, Y y, Z z, Zs... zs) { auto cont = vectors(y, z, zs...); return vector<decltype(cont)>(x, cont); }

inline ll square(ll x) { return x * x; }
inline ll gcd(ll a, ll b) { while(a) swap(a, b%=a); return b; }
inline ll lcm(ll a, ll b) { return a/gcd(a,b)*b; }
template <typename T>
inline T mod(T a, T b) { return ((a % b) + b) % b; }

template <typename T>
int find_left(vector<T>& v, T elem) {
    return (int)(upper_bound(v.begin(), v.end(), elem) - v.begin()) - 1;
}
template <typename T>
int find_right(vector<T>& v, T elem) {
    return (int)(lower_bound(v.begin(), v.end(), elem) - v.begin());
}

const ll MOD=1000000007LL;

inline ll ADD(ll x, ll y) { return (x+y) % MOD; }
inline ll SUB(ll x, ll y) { return (x-y+MOD) % MOD; }
inline ll MUL(ll x, ll y) { return x*y % MOD; }
inline ll POW(ll x, ll e) { ll v=1; for(; e; x=MUL(x,x), e>>=1) if (e&1) v = MUL(v,x); return v; }
inline ll INV(ll y) { /*assert(y%MOD!=0);*/ return POW(y, MOD-2); }
inline ll DIV(ll x, ll y) { return MUL(x, INV(y)); }

template <typename TYPE>
class UnionFindTree
{
private:
    std::vector<TYPE> parent_;
    std::vector<TYPE> rank_;
    std::vector<TYPE> size_;
    size_t find(size_t i)
    {
        assert(i < parent_.size());
        size_t j = (size_t)parent_[i];
        if (i != j)
        {
            j = find(j);
            parent_[i] = (TYPE)j;
        }
        return j;
    }

public:
    UnionFindTree(size_t n)
        : parent_(n), rank_(n, (TYPE)0), size_(n, (TYPE)1)
    {
        for (size_t i(0); i < n; ++i)
        {
            parent_[i] = (TYPE)i;
        }
    }
    ~UnionFindTree()
    {
        ;
    }
    void
    unite(size_t i,
          size_t j)
    {
        assert(i < parent_.size());
        assert(j < parent_.size());
        i = find(i);
        j = find(j);
        if (i == j)
            return;
        if (rank_[i] < rank_[j])
            std::swap<size_t>(i, j);
        parent_[j] = (TYPE)i;
        if (rank_[i] == rank_[j])
            rank_[i]++;
        size_[i] += size_[j];
    }
    bool
    same(size_t i,
         size_t j)
    {
        assert(i < parent_.size());
        assert(j < parent_.size());
        return find(i) == find(j);
    }
    TYPE
    size(size_t i)
    {
        assert(i < parent_.size());
        i = find(i);
        return size_[i];
    }
};

int main()
{
    int N, M;
    cin >> N >> M;

    int a[M], b[M];

    rep(i, M){
        cin >> a[i] >> b[i];
    }

    int ans = 0;
    rep(i, M){
        UnionFindTree<int> tree(N);
        int size;
        rep(j, M){
            if (i == j){continue;}
            tree.unite(a[j] - 1, b[j] - 1);
            size = tree.size(a[i] - 1);
        }
        if (size < N){ans += 1;}
    }
    cout << ans << endl;
}

Measured memory_bytes: 256