#include <iostream>
#include <fstream>

using namespace std;
ifstream fin("dfs.in");
ofstream out("dfs.out");
int n,sum,a[3010][3010],viz[3010];
void df(int i)
{
    int j;
    viz[i]=1;
    for(j=1;j<=n;j++)
        if(a[i][j]==1 && viz[j]==0)
        df(j);
    //    cout<<i<<" ";
}

int main()
{
    int m,i,j,p1,s2;
    fin>>n>>m;
    for(i=1;i<=m;i++)
 {
fin>>p1>>s2;
a[p1][s2]=1;
a[s2][p1]=1;
}
    for(i=1;i<=n;i++)
    if(viz[i]==0)
    {
        sum++;
        df(i);
        out<<endl;
    }
    out<<sum<<"\n";
    return 0;
}