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

graph = [[0 for i in range(N)] for j in range(N)]

edges = []

for m in range(M):

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

    a -= 1

    b -= 1

    edges.append([a,b])

    graph[a][b] = 1

    graph[b][a] = 1



ans = 0

for a,b in edges:

    graph[a][b] = 0

    graph[b][a] = 0



    visited = [False] * N

    visited[0] = True

    q = [i for i in range(N) if graph[0][i]]



    while q:

        r = q.pop(0)

        visited[r] = True

        for i in range(N):

            if graph[r][i] and not visited[i]:

                q.append(i)



    if False in visited:

        ans += 1



    graph[a][b] = 1

    graph[b][a] = 1



print(ans)
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())



def main():

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

    G = []

    for _ in range(M):

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

        a -= 1

        b -= 1

        G.append((a,b))

    ans = 0

    for i in range(M):

        uni = UnionFind(N)

        for j in range(M):

            if i == j:

                continue

            uni.union(G[j][0],G[j][1])

        if uni.group_count() >= 2:

            ans += 1



    print(ans)

if __name__ == "__main__":

    main()
N, M = list(map(int, input().split()))
graph = [[0 for i in range(N)] for j in range(N)]
edges = []
for m in range(M):
    a, b = list(map(int, input().split()))
    a -= 1
    b -= 1
    edges.append([a, b])
    graph[a][b] = 1
    graph[b][a] = 1
ans = 0
for a, b in edges:
    graph[a][b] = 0
    graph[b][a] = 0
    visited = [False] * N
    visited[0] = True
    q = [i for i in range(N) if graph[0][i]]
    while q:
        r = q.pop(0)
        visited[r] = True
        for i in range(N):
            if graph[r][i] and not visited[i]:
                q.append(i)
    if False in visited:
        ans += 1
    graph[a][b] = 1
    graph[b][a] = 1
print(ans)

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())


def main():
    N, M = list(map(int, input().split()))
    G = []
    for _ in range(M):
        a, b = list(map(int, input().split()))
        a -= 1
        b -= 1
        G.append((a, b))
    ans = 0
    for i in range(M):
        uni = UnionFind(N)
        for j in range(M):
            if i == j:
                continue
            uni.union(G[j][0], G[j][1])
        if uni.group_count() >= 2:
            ans += 1
    print(ans)


if __name__ == "__main__":
    main()

-N, M = list(map(int, input().split())) -graph = [[0 for i in range(N)] for j in range(N)] -edges = [] -for m in range(M): -    a, b = list(map(int, input().split())) -    a -= 1 -    b -= 1 -    edges.append([a, b]) -    graph[a][b] = 1 -    graph[b][a] = 1 -ans = 0 -for a, b in edges: -    graph[a][b] = 0 -    graph[b][a] = 0 -    visited = [False] * N -    visited[0] = True -    q = [i for i in range(N) if graph[0][i]] -    while q: -        r = q.pop(0) -        visited[r] = True -        for i in range(N): -            if graph[r][i] and not visited[i]: -                q.append(i) -    if False in visited: -        ans += 1 -    graph[a][b] = 1 -    graph[b][a] = 1 -print(ans) +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()) + + +def main(): +    N, M = list(map(int, input().split())) +    G = [] +    for _ in range(M): +        a, b = list(map(int, input().split())) +        a -= 1 +        b -= 1 +        G.append((a, b)) +    ans = 0 +    for i in range(M): +        uni = UnionFind(N) +        for j in range(M): +            if i == j: +                continue +            uni.union(G[j][0], G[j][1]) +        if uni.group_count() >= 2: +            ans += 1 +    print(ans) + + +if __name__ == "__main__": +    main()