CF720B.Cactusophobia

Tree is a connected undirected graph that has no cycles. Edge cactus is a connected undirected graph without loops and parallel edges, such that each edge belongs to at most one cycle.

Vasya has an edge cactus, each edge of this graph has some color.

Vasya would like to remove the minimal number of edges in such way that his cactus turned to a tree. Vasya wants to make it in such a way that there were edges of as many different colors in the resulting tree, as possible. Help him to find how many different colors can the resulting tree have.

树是无环的连通无向图。边仙人掌图（edge cactus）是无自环、无重边的连通无向图，且每条边至多属于一个环。

瓦西娅有一棵边仙人掌图，该图的每条边均被赋予某种颜色。

瓦西娅希望删除最少数量的边，使得该仙人掌图变为一棵树。同时，他希望在满足删除边数最少的前提下，使最终得到的树中包含尽可能多种不同颜色的边。请帮助他求出该树最多能包含多少种不同的颜色。

The first line contains two integers: n, m (2 ≤ n ≤ 10 000) — the number of vertices and the number of edges in Vasya's graph, respectively.

The following m lines contain three integers each: u, v, c (1 ≤ u, v ≤ n, u ≠ v, 1 ≤ c ≤ m) — the numbers of vertices connected by the corresponding edge, and its color. It is guaranteed that the described graph is indeed an edge cactus.

第一行包含两个整数：$n$、$m$（$2 \leq n \leq 10\,000$），分别表示 Vasya 图中的顶点数和边数。

接下来的 $m$ 行每行包含三个整数：$u$、$v$、$c$（$1 \leq u,\,v \leq n$，$u \neq v$，$1 \leq c \leq m$），表示由该边连接的两个顶点编号及其颜色。题目保证所描述的图确实是一个边仙人掌图（edge cactus）。

Output one integer: the maximal number of different colors that the resulting tree can have.

输出一个整数：所得树所能拥有的最多不同颜色数量。