#include <iostream>
#include <fstream>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
int n,m,v[400001],v1[400001],v2[200001],n1;
bool v3[200001];
void a(int i,int j)
{
    n1++;
    v[n1]=j;
    v1[n1]=v2[i];
    v2[i]=n1;
}
void dfs(int x)
{
    v3[x]=1;
    for (int i=v2[x];i!=0;i=v1[i])
    {
        int j=v[i];
        if(v3[j]!=0)
            dfs(j);
    }
}
int main()
{
    int k=0;
    f>>n>>m;
    for (int i=0;i<m;i++)
    {
        int x,y;
        f>>x>>y;
        a(x,y);
        a(y,x);
    }
    for (int i=1;i<=n;i++)
    {
        if (v3[i]!=0)
        {
            k++;
            dfs(i);
        }
    }
    g<<k;
    return 0;
}