nm = [int(x) for x in input().split(" ")]
num_sites = nm[0]
num_edges = nm[1]

graph = [] #adjacency matrix
graph2 = {} #adjacency list
edges = [] #list of edges
all_sites = list(range(0, num_sites))

for _ in range (num_sites):
    graph.append([0] * num_sites)
    graph2[_] = []

for _ in range(num_edges):
    pair = [int(x) for x in input().split(" ")]
    graph[pair[0]][pair[1]] = 1
    graph[pair[1]][pair[0]] = 1
    graph2[pair[0]].append(pair[1])
    graph2[pair[1]].append(pair[0])
    edges.append((pair[0], pair[1]))

def solve(all_sites, index, included_sites, results):
    if index >= len(all_sites):
        results.append(included_sites)
        return 0

    new_included_sites = included_sites[:]
    new_included_sites.append(all_sites[index])



    solve(all_sites, index + 1, new_included_sites, results)
    solve(all_sites, index + 1, included_sites, results)

    return 0




def check(included_sites, edges):
    #print(included_sites)
    for edge in edges:
        if edge[0] not in included_sites and edge[1] not in included_sites:
            return False
    return True

index = 0
results = []
solve(all_sites, index, [], results)
results = [x for x in results if check(x, edges)]
#print(edges)
print(min([len(x) for x in results]))