Problem Statement

There are N cards placed face down in a row. On each card, an integer 1 or 2 is written.
Let A_i be the integer written on the i-th card.
Your objective is to guess A_1, A_2, ..., A_N correctly.
You know the following facts:

• For each i = 1, 2, ..., M, the value A_{X_i} + A_{Y_i} + Z_i is an even number.

You are a magician and can use the following magic any number of times:
Magic: Choose one card and know the integer A_i written on it. The cost of using this magic is 1.
What is the minimum cost required to determine all of A_1, A_2, ..., A_N?
It is guaranteed that there is no contradiction in given input.

Input

Input is given from Standard Input in the following format:
N M
X_1 Y_1 Z_1
X_2 Y_2 Z_2
$\vdots$
X_M Y_M Z_M

Output

Print the minimum total cost required to determine all of A_1, A_2, ..., A_N.

Constraints

• All values in input are integers.
• $2 \leq N \leq 10^5$
• $1 \leq M \leq 10^5$
• $1 \leq X_i < Y_i \leq N$
• $1 \leq Z_i \leq 100$
• The pairs (X_i, Y_i) are distinct.
• There is no contradiction in input. (That is, there exist integers A_1, A_2, ..., A_N that satisfy the conditions.)

Sample Input 1

3 1
1 2 1

Sample Output 1

2

You can determine all of A_1, A_2, A_3 by using the magic for the first and third cards.

Sample Input 2

6 5
1 2 1
2 3 2
1 3 3
4 5 4
5 6 5

Sample Output 2

2

Sample Input 3

100000 1
1 100000 100

Sample Output 3

99999

见题面 Input 部分

见题面 Output 部分