/*
このコード、と～おれ!
Be accepted!
∧＿∧　
（｡･ω･｡)つ━☆・*。
⊂　　 ノ 　　　・゜+.
　しーＪ　　　°。+ *´¨)
 　　　　　　　　　.· ´¸.·*´¨) ¸.·*¨)
		  　　　　　　　　　　(¸.·´ (¸.·'* ☆
*/

#include <cstdio>
#include <algorithm>
#include <string>
#include <cmath>
#include <cstring>
#include <vector>
#include <numeric>
#include <iostream>
#include <random>
#include <map>
#include <unordered_map>
#include <queue>
#include <regex>
#include <functional>
#include <complex>
#include <list>
#include <cassert>
#include <iomanip>
#include <set>
#include <stack>
/*多倍長整数/cpp_intで宣言
#include <boost/multiprecision/cpp_int.hpp>
using namespace boost::multiprecision;
*/

//#pragma gcc target ("avx2")
//#pragma gcc optimization ("o3")
//#pragma gcc optimization ("unroll-loops")
#define rep(i, n) for(int i = 0; i < (n); ++i)
#define rep1(i, n) for(int i = 1; i <= (n); ++i)
#define rep2(i, n) for(int i = 2; i < (n); ++i)
#define repr(i, n) for(int i = n; i >= 0; --i)
#define reprm(i, n) for(int i = n - 1; i >= 0; --i)
#define printynl(a) printf(a ? "yes\n" : "no\n")
#define printyn(a) printf(a ? "Yes\n" : "No\n")
#define printYN(a) printf(a ? "YES\n" : "NO\n")
#define printim(a) printf(a ? "possible\n" : "imposible\n")
#define printdb(a) printf("%.50lf\n", a) //少数出力
#define printLdb(a) printf("%.50Lf\n", a) //少数出力
#define printdbd(a) printf("%.16lf\n", a) //少数出力(桁少なめ)
#define prints(s) printf("%s\n", s.c_str()) //string出力
#define all(x) (x).begin(), (x).end()
#define allsum(a, b, c) ((a + b) * c / 2LL) //等差数列の和、初項,末項,項数
#define pb push_back
#define priq priority_queue
#define rpriq priq<int, vector<int>, greater<int>>
#define deg_to_rad(deg) (((deg)/360.0L)*2.0L*PI)
#define rad_to_deg(rad) (((rad)/2.0L/PI)*360.0L)
#define Please return
#define AC 0
#define manhattan_dist(a, b, c, d) (abs(a - c) + abs(b - d)) /*(a, b) から (c, d) のマンハッタン距離 */


using ll = long long;

constexpr int INF = 1073741823;
constexpr int MINF = -1073741823;
constexpr ll LINF = ll(4661686018427387903);
constexpr ll MOD = 1000000007;
const long double PI = acosl(-1.0L);

using namespace std;

void scans(string& str) {
	char c;
	str = "";
	scanf("%c", &c);
	if (c == '\n')scanf("%c", &c);
	while (c != '\n' && c != -1 && c != ' ') {
		str += c;
		scanf("%c", &c);
	}
}

void scanc(char& str) {
	char c;
	scanf("%c", &c);
	if (c == -1)return;
	while (c == '\n') {
		scanf("%c", &c);
	}
	str = c;
}

double acot(double x) {
	return PI / 2 - atan(x);
}

ll gcd(ll a, ll b) {
	if (b == 0) return a;
	return gcd(b, a % b);
}

ll lcm(ll number1, ll number2) {
	return number1 / gcd(number1, number2) * number2;
}

ll LSB(ll n) { return (n & (-n)); }

/*-----------------------------------------ここからコード-----------------------------------------*/

template< typename T >
struct edge {
    int src, to;
    T cost;

    edge(int to, T cost) : src(-1), to(to), cost(cost) {}

    edge(int src, int to, T cost) : src(src), to(to), cost(cost) {}

    edge& operator=(const int& x) {
        to = x;
        return *this;
    }

    operator int() const { return to; }
};

template< typename T >
using Edges = vector< edge< T > >;
template< typename T >
using WeightedGraph = vector< Edges< T > >;
using UnWeightedGraph = vector< vector< int > >;
template< typename T >
using Matrix = vector< vector< T > >;

template< typename G >
struct LowLink {
    const G& g;
    vector< int > used, ord, low;
    vector< int > articulation;
    vector< pair< int, int > > bridge;

    LowLink(const G& g) : g(g) {}

    int dfs(int idx, int k, int par) {
        used[idx] = true;
        ord[idx] = k++;
        low[idx] = ord[idx];
        bool is_articulation = false;
        int cnt = 0;
        for (auto& to : g[idx]) {
            if (!used[to]) {
                ++cnt;
                k = dfs(to, k, idx);
                low[idx] = min(low[idx], low[to]);
                is_articulation |= ~par && low[to] >= ord[idx];
                if (ord[idx] < low[to]) bridge.emplace_back(minmax(idx, (int)to));
            }
            else if (to != par) {
                low[idx] = min(low[idx], ord[to]);
            }
        }
        is_articulation |= par == -1 && cnt > 1;
        if (is_articulation) articulation.push_back(idx);
        return k;
    }

    virtual void build() {
        used.assign(g.size(), 0);
        ord.assign(g.size(), 0);
        low.assign(g.size(), 0);
        int k = 0;
        for (int i = 0; i < g.size(); i++) {
            if (!used[i]) k = dfs(i, k, -1);
        }
    }
};
//うしさんに感謝

int main() {

    int n, m, a, b;
    scanf("%d%d", &n, &m);
    UnWeightedGraph graph(n);
    rep(i, m) {
        scanf("%d%d", &a, &b);
        --a; --b;
        graph[a].pb(b);
        graph[b].pb(a);
    }
    LowLink<UnWeightedGraph> lowlink(graph);
    lowlink.build();
    printf("%d\n", (int)lowlink.bridge.size());

	Please AC;
}


Measured memory_bytes: 888