#include <fstream>

using namespace std;

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

int n, m;
bool viz[200005], a[1005][1005];

void Citire()
{
    int i,x,y;
    fin>>n>>m;
    for( i= 1 ; i <= m ; i++)
    {
        fin>>x>>y;
        a[x][y]=a[y][x]=1;
    }
}

void DFS( int k)
{
    viz[k]=1;
    for(int i = 1 ; i <= n ; i++)
        if(viz[i] == 0 && a[k][i]==1)
            DFS(i);
}

int main()
{
    Citire();
    int i,nrc=0;
    for( i = 1 ; i <= n ; i++)
        if(viz[i]==0)
        {
            DFS(i);
            nrc++;
        }
    fout<<nrc<<"\n";
    return 0;
}