if __name__ == "__main__":

num_nodes, num_edges = list(map(int, input().strip().split()))

edges = []

for i in range(num_edges):

node1, node2, cost = list(map(int, input().strip().split()))

edges.append((i, node1, node2, cost))

edges = sorted(edges, key=lambda edge: edge[3])

parent = list(range(num_nodes))

def find_parent(i):

if i != parent[i]:

parent[i] = find_parent(parent[i])

return parent[i]

minimum_spanning_tree_cost = 0

minimum_spanning_tree = []

for edge in edges:

parent_a = find_parent(edge[1])

parent_b = find_parent(edge[2])

if parent_a != parent_b:

minimum_spanning_tree_cost += edge[3]

minimum_spanning_tree.append(edge)

parent[parent_a] = parent_b

print(minimum_spanning_tree_cost)

for edge in minimum_spanning_tree:

print(edge)