import sys



class UnionFind():

    def __init__(self, n):

        self.n = n

        self.parents = [-1] * n



    def find(self, x):

        if self.parents[x] < 0:

            return x

        else:

            self.parents[x] = self.find(self.parents[x])

            return self.parents[x]



    def union(self, x, y):

        x = self.find(x)

        y = self.find(y)



        if x == y:

            return



        if self.parents[x] > self.parents[y]:

            x, y = y, x



        self.parents[x] += self.parents[y]

        self.parents[y] = x



    def size(self, x):

        return -self.parents[self.find(x)]



    def same(self, x, y):

        return self.find(x) == self.find(y)



    def members(self, x):

        root = self.find(x)

        return [i for i in range(self.n) if self.find(i) == root]



    def roots(self):

        return [i for i, x in enumerate(self.parents) if x < 0]



    def group_count(self):

        return len(self.roots())



    def all_group_members(self):

        return {r: self.members(r) for r in self.roots()}



    def __str__(self):

        return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots())



N, M = list(map(int, sys.stdin.readline().rstrip().split()))

edges = []

for _ in range(M):

    a, b = list(map(int, sys.stdin.readline().rstrip().split()))

    edges.append((a-1, b-1))



ans = 0

for i in range(M):

    uf = UnionFind(N)

    for j, (a, b) in enumerate(edges):

        if i == j:

            continue

        uf.union(a, b)

    if uf.group_count() != 1:

        ans += 1



print(ans)
import sys

from collections import deque



input = sys.stdin.readline

N, M = list(map(int, input().split()))



edges = [[] for _ in range(N)]

edge_set = set()

for _ in range(M):

    a, b = list(map(int, input().split()))

    a -= 1

    b -= 1

    edges[a].append(b)

    edges[b].append(a)



    edge_set.add((a, b))



ans = 0

for a, b in edge_set:

    q = deque()

    q.append(0)

    visited = set()

    while q:

        p = q.popleft()

        if p in visited:

            continue

        visited.add(p)

        for np in edges[p]:

            if (p, np) == (a, b) or (np, p) == (a, b):

                continue

            q.append(np)

    if len(visited) != N:

        ans += 1



print(ans)
import sys


class UnionFind:
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if x == y:
            return
        if self.parents[x] > self.parents[y]:
            x, y = y, x
        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def size(self, x):
        return -self.parents[self.find(x)]

    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        return {r: self.members(r) for r in self.roots()}

    def __str__(self):
        return "\n".join("{}: {}".format(r, self.members(r)) for r in self.roots())


N, M = list(map(int, sys.stdin.readline().rstrip().split()))
edges = []
for _ in range(M):
    a, b = list(map(int, sys.stdin.readline().rstrip().split()))
    edges.append((a - 1, b - 1))
ans = 0
for i in range(M):
    uf = UnionFind(N)
    for j, (a, b) in enumerate(edges):
        if i == j:
            continue
        uf.union(a, b)
    if uf.group_count() != 1:
        ans += 1
print(ans)

import sys
from collections import deque

input = sys.stdin.readline
N, M = list(map(int, input().split()))
edges = [[] for _ in range(N)]
edge_set = set()
for _ in range(M):
    a, b = list(map(int, input().split()))
    a -= 1
    b -= 1
    edges[a].append(b)
    edges[b].append(a)
    edge_set.add((a, b))
ans = 0
for a, b in edge_set:
    q = deque()
    q.append(0)
    visited = set()
    while q:
        p = q.popleft()
        if p in visited:
            continue
        visited.add(p)
        for np in edges[p]:
            if (p, np) == (a, b) or (np, p) == (a, b):
                continue
            q.append(np)
    if len(visited) != N:
        ans += 1
print(ans)

+from collections import deque - -class UnionFind: -    def __init__(self, n): -        self.n = n -        self.parents = [-1] * n - -    def find(self, x): -        if self.parents[x] < 0: -            return x -        else: -            self.parents[x] = self.find(self.parents[x]) -            return self.parents[x] - -    def union(self, x, y): -        x = self.find(x) -        y = self.find(y) -        if x == y: -            return -        if self.parents[x] > self.parents[y]: -            x, y = y, x -        self.parents[x] += self.parents[y] -        self.parents[y] = x - -    def size(self, x): -        return -self.parents[self.find(x)] - -    def same(self, x, y): -        return self.find(x) == self.find(y) - -    def members(self, x): -        root = self.find(x) -        return [i for i in range(self.n) if self.find(i) == root] - -    def roots(self): -        return [i for i, x in enumerate(self.parents) if x < 0] - -    def group_count(self): -        return len(self.roots()) - -    def all_group_members(self): -        return {r: self.members(r) for r in self.roots()} - -    def __str__(self): -        return "\n".join("{}: {}".format(r, self.members(r)) for r in self.roots()) - - -N, M = list(map(int, sys.stdin.readline().rstrip().split())) -edges = [] +input = sys.stdin.readline +N, M = list(map(int, input().split())) +edges = [[] for _ in range(N)] +edge_set = set() -    a, b = list(map(int, sys.stdin.readline().rstrip().split())) -    edges.append((a - 1, b - 1)) +    a, b = list(map(int, input().split())) +    a -= 1 +    b -= 1 +    edges[a].append(b) +    edges[b].append(a) +    edge_set.add((a, b)) -for i in range(M): -    uf = UnionFind(N) -    for j, (a, b) in enumerate(edges): -        if i == j: +for a, b in edge_set: +    q = deque() +    q.append(0) +    visited = set() +    while q: +        p = q.popleft() +        if p in visited: -        uf.union(a, b) -    if uf.group_count() != 1: +        visited.add(p) +        for np in edges[p]: +            if (p, np) == (a, b) or (np, p) == (a, b): +                continue +            q.append(np) +    if len(visited) != N: