Problem:
Score : 500 points

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.

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.)

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.

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

Solution in C++14 (GCC 5.4.1) (judge verdict: Accepted)

/* while(!success_achieved())
      work_hard();

   code by:aman_ayush
  */
#include <bits/stdc++.h>
using namespace std;

#define fast ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0)
#define ll long long
#define ldb long double 
#define db double
#define str string

#define fr first
#define se second
#define lb lower_bound 
#define ub upper_bound 
#define pb push_back
#define mp make_pair

#define pi pair<int,int>
#define pll pair<ll,ll>
#define pdb pair<db,db>
#define pldb pair<ldb,ldb>

#define vi vector<int>
#define vll vector<ll>
#define vdb vector<db>
#define vldb vector<ldb>
#define vpi vector< pi >
#define vpll vector< pll >

#define mi map<int,int>
#define mll map<ll,ll>
#define mdb map<db,db>
#define mldb map<ldb,ldb>


#define forr(a,b) for (int i = (a); i < (b); ++i)
#define rrof(a,b) for (int i = (b)-1; i >= (a); --i)

#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)

const int MOD = 1e9+7;
const int MX = 2e5+5;
const ll INF = 1e18; 
const ldb PI = 4*atan((ldb)1);

ll power(ll a,ll n)
{
 ll res=1;
 while(n)
{
 if(n%2)
  res*=a;
  a*=a;
  n/=2;
}
return res;
}

ll abst(ll a)
{
 return ((a<0)?(-1*a):(a));
}
bool vis[100001];

void bfs(int s,int n,vi v[])
{
    vis[s]=true;
    queue<int> q;
    q.push(s);
    while(!q.empty())
    {
        int r=q.front();
        q.pop();
        for(int i=0;i<v[r].size();i++)
        {
            int ch=v[r][i];
            if(!vis[ch])
            {
                q.push(ch);
                vis[ch]=true;
            }
        }
    }
}
int main()
{
    for(int i=0;i<=100000;i++)
     vis[i]=false;
    fast;
     int n,m;
     cin>>n>>m;
     vi v[n+1];
     for(int i=1;i<=m;i++)
     {
         int x,y,z;
         cin>>x>>y>>z;
         v[x].push_back(y);
         v[y].push_back(x);
     }
     int count=0;
     for(int i=1;i<=n;i++)
     {
         if(!vis[i])
         {
             count++;
             bfs(i,n,v);
         }
     }
     cout<<count<<"\n";
     return 0;
}