#include <iostream>
#include <cstdio>
#include <vector>
#include <bitset>
#define N 2000005
using namespace std;
vector <int> G[N];
bitset <N> p;
int x,y,n,m,nr=0;
void dfs(int st)
{
    p[st]=1;
    vector <int>::iterator it;
    for(it=G[st].begin();it!=G[st].end();++it)
    {
        if(!p[*it])
            dfs(*it);
    }
}
void citire()
{
    scanf("%d %d\n",&n,&m);
    for(int i=1;i<=m;i++)
    {
        scanf("%d %d\n",&x,&y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
}
int main()
{
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    citire();
    for(int i=1;i<=n;i++)
    {
        if(p[i]==0)
            {
                dfs(i);
                nr++;
            }
    }
    printf("%d",nr);
    //cout << "Hello world!" << endl;
    return 0;
}