#include <cstdio>
#include <vector>
#define NR_NOD 100000
using namespace std;
bool viz[NR_NOD];
vector <int> v[NR_NOD];
void dfs(int nod)
{
    viz[nod]=true;
    for(unsigned int i=0;i<v[nod].size();i++)
        if(!viz[v[nod][i]])
            dfs(v[nod][i]);
}
int main()
{
    FILE *fin,*fout;
    fin=fopen("dfs.in","r");
    fout=fopen("dfs.out","w");
    int n,m,x,y,co=0;
    fscanf(fin,"%d%d",&n,&m);
    for(int i=0;i<m;i++)
    {
        fscanf(fin,"%d%d",&x,&y);
        v[x-1].push_back(y-1);
        v[y-1].push_back(x-1);
    }
    for(int i=0;i<n;i++)
        if(!viz[i])
            dfs(i),co++;
    fprintf(fout,"%d",co);
    fclose(fin);
    fclose(fout);
    return 0;
}