#include <fstream>

using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
int n,m,i,j,x,y,a[100001][100001];
bool sel[100001];
void build()
{
    int i,j;
    f>>n>>m;
    for (i=1; i<=n; i++)
        for (j=1; j<=n; j++) a[i][j]=0;
    for (i=1; i<=m; i++)
    {
        f>>x>>y;
        a[x][y]=1;
        a[y][x]=1;
    }
    for (i=1;i<=n;i++) sel[i]=false;
}
void DF(int x)
{
    int i;
    sel[x]=true;
    for (i=1;i<=n;i++)
        if (a[x][i]==1 && !sel[i]) DF(i);
}
int main()
{
    build();
    int nr=0;
    for (i=1;i<=n;i++)
    {
        if (sel[i]==false)
        {
            nr++;
            DF(i);
        }
    }
    g<<nr;
    return 0;
}