#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;;
const int NMAX=100005;
vector <int> graph[NMAX];
bool viz[NMAX];
void dfs(int node)
{
    viz[node]=1;
    for(auto neigh : graph[node])
    {
        if(viz[neigh]==0)
            dfs(neigh);
    }
}
int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    int n,m,i,x,y,cnt=0;
    scanf("%d%d",&n,&m);
    for(i=1;i<=m;i++)
    {
        scanf("%d%d",&x,&y);
        graph[x].push_back(y);
        graph[y].push_back(x);
    }
    for(i=1;i<=n;i++)
        sort(graph[i].begin(),graph[i].end());
    for(i=1;i<=n;i++)
    {
        if(!viz[i])
        {
            dfs(i);
            cnt++;
        }
    }
    printf("%d",cnt);
    fclose(stdin);
    fclose(stdout);
    return 0;
}