from collections import deque

class Node():
    def __init__(self, id):
        self.id = id
        self.state = 0
        self.children = []

###

n,m = list(map(int, input().split(' ')))        

scores = []
for i in range(n):
    r = [0] * n
    scores.append(r)

children = {}
for i in range(m):
    p,c,s = list(map(int, input().split(' ')))
    if p not in children:
        children[p] = [c]
    else:
        children[p].append(c)
    scores[p][c] = s

###

nodes = []
for p in range(n):
    nodes.append(Node(p))

for parent in nodes:
    for c in sorted(children[parent.id]):
        parent.children.append(nodes[c])

###

def dfs(parent, parents, sum, sums):
    parent.status = 1
    for child in parent.children:
        if child.status == 0:
            parents.append(parent)
            for p in parents:
                sum += scores[p.id][child.id]
            dfs(child, parents, sum, sums)
        else:
            sums.append(sum)

def reset():
    for node in nodes:
        node.status = 0
        for child in node.children:
            child.status = 0

###

sums = []            
for parent in nodes:
    for child in parent.children:
        reset()
        parent.status = 1        
        dfs(child, [parent], scores[parent.id][child.id], sums)

print(sorted(sums)[len(sums)-1])