#include <fstream>

using namespace std;
ifstream in ("dfs.in");
ofstream out("dfs.out");
int a[1001][1001],viz[1001],n,m;
void dfs (int k)
{
    viz[k]=1;
    for (int i=1;i<=n;i++)
        if (a[i][k]==1&&viz[i]==0)
        dfs(i);
}
int main()
{
    int cnt=0,x,y;
    in>>n>>m;
    for (int i=1;i<=m;i++)
    {
        in>>x>>y;
        a[x][y]=a[y][x]=1;
    }
    for (int i=1;i<=n;i++)
        if (viz[i]==0)
        {
            cnt++;
            dfs(i);
        }
    out<<cnt<<endl;
    return 0;
}