package main

import (
	"bufio"
	"fmt"
	"log"
	"os"
	"strconv"
)

// const abcd = "abcdefghijklnmopqrstuvwxyz"
// const ABCD = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

// var dy = [...]int{1, 1, 0, -1, -1, -1, 0, 1}
// var dx = [...]int{0, 1, 1, 1, 0, -1, -1, -1}

// var dx = [...]int{0, 1, 0, -1}
// var dy = [...]int{1, 0, -1, 0}

// ---------------------------------------------------------
func main() {
	log.SetFlags(log.Lshortfile)
	next := newScanner()
	N := next.Int()
	M := next.Int()
	a := make([]int, M)
	b := make([]int, M)
	for i := 0; i < M; i++ {
		a[i] = next.Int() - 1
		b[i] = next.Int() - 1
	}
	g := make([][]bool, N)
	for i := 0; i < N; i++ {
		g[i] = make([]bool, N)
	}
	for i := 0; i < M; i++ {
		g[a[i]][b[i]] = true
		g[b[i]][a[i]] = true
	}
	ans := 0
	visited := make([]bool, N)
	var dfs func(int)
	dfs = func(u int) {
		visited[u] = true
		for v := 0; v < N; v++ {
			if !g[u][v] || visited[v] {
				continue
			}
			dfs(v)
		}
	}
	for i := 0; i < M; i++ {
		g[a[i]][b[i]] = false
		g[b[i]][a[i]] = false
		visited = make([]bool, N)
		dfs(0)
		bridge := false
		for j := 0; j < N; j++ {
			if !visited[j] {
				bridge = true
			}
		}
		if bridge {
			ans++
		}
		g[a[i]][b[i]] = true
		g[b[i]][a[i]] = true
	}

	// var ans int
	fmt.Println(ans)
}

// ---------------------------------------------------------

// Pair is liked C++ pair
type Pair struct {
	first, second int
}

// Pairs is sorted by []Pair struct
type Pairs []Pair

func (p Pairs) Len() int {
	return len(p)
}
func (p Pairs) Swap(i, j int) {
	p[i], p[j] = p[j], p[i]
}

func (p Pairs) Less(i, j int) bool {
	if p[i].first < p[j].first {
		return true
	} else if p[i].first == p[j].first {
		return p[i].second < p[j].second
	}
	return false
}

// -------------------------------
func in(c, a, z int) bool {
	return c >= a && c < z
}

func btoi(b bool) int {
	if b {
		return 1
	}
	return 0
}

func itob(a int) bool {
	if a == 0 {
		return false
	}
	return true
}

func max(a ...int) int {
	r := a[0]
	for i := 0; i < len(a); i++ {
		if r < a[i] {
			r = a[i]
		}
	}
	return r
}

func min(a ...int) int {
	r := a[0]
	for i := 0; i < len(a); i++ {
		if r > a[i] {
			r = a[i]
		}
	}
	return r
}

func minmax(a, b int) (int, int) {
	if a > b {
		return b, a
	}
	return a, b
}

func abs(a int) int {
	if a < 0 {
		return -a
	}
	return a
}

// ---------- buffered scanner -----------------------------------------
type scanner struct {
	r   *bufio.Reader
	buf []byte
	p   int
}

func newScanner() *scanner {
	rdr := bufio.NewReaderSize(os.Stdin, 10000)
	return &scanner{r: rdr}
}
func (s *scanner) next() string {
	s.pre()
	start := s.p
	for ; s.p < len(s.buf); s.p++ {
		if s.buf[s.p] == ' ' {
			break
		}
	}
	result := string(s.buf[start:s.p])
	s.p++
	return result
}
func (s *scanner) Line() string {
	s.pre()
	start := s.p
	s.p = len(s.buf)
	return string(s.buf[start:])
}
func (s *scanner) Int() int {
	v, _ := strconv.Atoi(s.next())
	return v
}
func (s *scanner) Int64() int64 {
	v, _ := strconv.ParseInt(s.next(), 10, 64)
	return v
}
func (s *scanner) pre() {
	if s.p >= len(s.buf) {
		s.readLine()
		s.p = 0
	}
}
func (s *scanner) readLine() {
	s.buf = make([]byte, 0)
	for {
		l, p, e := s.r.ReadLine()
		if e != nil {
			panic(e)
		}
		s.buf = append(s.buf, l...)
		if !p {
			break
		}
	}
}


Measured memory_bytes: 640