#include<vector>
#include<fstream>
using namespace std;
 
ifstream f("dfs.in");
ofstream g("dfs.out");
 
#define MAXN 100003
 
vector<int> G[MAXN];
bool v[MAXN];
int n,m;
int nr;
 
int read()
{
    f>>n;
    f>>m;
    int x,y;
 
    for(int i=1;i<=m;i++)
    {
        f>>x;
        f>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
 
    return 0;
}
 
int dfs(int nod)
{
    v[nod] = true;
 
    for(int i=0, length = G[nod].size(); i<length; i++)
    {
        if( v[ G[nod][i] ] != true )
        {
            dfs( G[nod][i] );
        }
    }
     
    return 0;
 
}
 
int write()
{
    g<<nr;
     
    return 0;
}
 
int main()
{   
    read();
 
    // Solve
    for(int i=1;i<=n;i++)
    {
        if(v[i] != true)
        {
            nr++;
            dfs(i);
        }
    }
 
    write();
 
    return 0; 
}