#!/usr/bin/env python3
import itertools

n, m = [int(x) for x in input().split()]

adj = [[] for _ in range(n)]
edge_list = []

for _ in range(m):
    a, b = [int(x) for x in input().split()]
    a -= 1
    b -= 1
    adj[a].append(b)
    adj[b].append(a)
    edge_list.append((min(a, b), max(a, b)))

# Find edges you can remove while keeping the graph connected.
removed_edges = []
for a, b in edge_list:
    seen = [True] + [False]*(n-1)
    stack = [0]
    while len(stack) != 0:
        cur = stack.pop()
        for nb in adj[cur]:
            if (cur, nb) != (a, b) and (nb, cur) != (a, b):
                if not seen[nb]:
                    stack.append(nb)
                    seen[nb] = True
    if all(seen):
        removed_edges.append((a, b))
        adj[a] = [x for x in adj[a] if x != b]
        adj[b] = [x for x in adj[b] if x != a]

root = 0
num_outgoing = [len(adj[i]) - 1 for i in range(n)]
num_outgoing[root] += 1
toposort = [x for x in range(n) if num_outgoing[x] == 0]
stack = [x for x in range(n) if num_outgoing[x] == 0]
parent = [-1]*n

while len(stack) > 0:
    cur = stack.pop()
    for nb in adj[cur]:
        if num_outgoing[nb] != 0:
            parent[cur] = nb
            num_outgoing[nb] -= 1
            if num_outgoing[nb] == 0:
                stack.append(nb)
                toposort.append(nb)

assert len(toposort) == n
assert parent[0] == -1
assert all(parent[x] >= 0 for x in range(1, n))

largest = 0

for l in itertools.product([0, 1], repeat=len(removed_edges)):
    off_verts = [p[i] for p, i in zip(removed_edges, l)]

    max_ind_used = [0]*n
    max_ind_unused = [0]*n

    for x in toposort:
        for nb in adj[x]:
            if nb != parent[x]:
                max_ind_unused[x] += max(max_ind_used[nb], max_ind_unused[nb])

        if x not in off_verts:
            max_ind_used[x] = 1
            for nb in adj[x]:
                if nb != parent[x]:
                    max_ind_used[x] += max_ind_unused[nb]
        else:
            max_ind_used[x] = max_ind_unused[x]
    largest = max(largest, max_ind_used[0], max_ind_unused[0])

print(largest)