#include <fstream>
#include<vector>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
int n,m,numar=0,v[100005];
vector<int>a[100005],w;

void cit()
{int i,j,k;
fin>>n>>m;
for(k=1;k<=m;k++)
    {
        fin>>i>>j;
        a[i].push_back(j);
        a[j].push_back(i);
    }
}


void dfs(int k)
{  int i;
    v[k]=1;
    for(i=0;i<a[k].size();i++)
        if(v[a[k][i]]==0)
        dfs(a[k][i]),w.push_back(a[k][i]);
}

void conex()
{
    int i;
    for(i=1;i<=n;i++)
        if(v[i]==0)
    {
        numar++;
        dfs(i);
    }
}



int main()
{
   cit();
    conex();
    fout<<numar;

    return 0;
}