#include <fstream>

using namespace std;

ifstream in("dfs.in");
ofstream out("dfs.out");

int v[2][1000000], start[1000000], c[1000000];
bool viza[100000];
int n, m;

void citire()
{
    int k=0, x, y;
    in>>n>>m;
    for(int i=1; i<=m; i++)
    {
        in>>x>>y;
        k++;
        v[0][k]=x;
        v[1][k]=start[y];
        start[y]=k;
        k++;
        v[0][k]=y;
        v[1][k]=start[x];
        start[x]=k;
    }
}

void dfs(int i)
{
    int st=1, dr=1, man;
    c[st]=i;
    while(st<=dr)
    {
        man=start[c[st]];
        while(man)
        {
            if(viza[v[0][man]]==0)
            {
                viza[v[0][man]]=1;
                c[++dr]=v[0][man];
            }
            man=v[1][man];
        }
        st++;
    }

}

int main()
{
    int nr=0;
    citire();
    for(int i=1; i<=n; i++)
    {
        if(viza[i]==0)
        {
            viza[i]=1;
            dfs(i);
            nr++;
        }
    }
    out<<nr;
    return 0;
}