#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
vector <int>v[100001];
char viz[100001];
int maxim;
void DFS(int i)
{
    int n=v[i].size();
    int k,j;
    for(j=n-1;j>=0;j--)
    {
        k=v[i][j];
        if(viz[k]==0)
        {
            viz[k]=1;
            DFS(k);
        }
    }
}
int main()
{
    int n,m,i,x,y;
    f>>n>>m;
    for(i=1;i<=m;i++)
    {
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(i=1;i<=n;i++)
    {
        if(viz[i]==0)
        {
            DFS(i);
            maxim++;
        }
    }
    g<<maxim;
    return 0;
}