#include <iostream>
#include <fstream>
#include <vector>
#define pb push_back
using namespace std;
ifstream in("dfs.in");
ofstream out("dfs.out");
int n,m,x,y,cont;
bool b[200005];
vector<int> v[100005];
int dx[4]={-1,0,1,0};
int dy[4]={0,1,0,-1};
void dfs(int nod)
{
    b[nod]=1;
    for(auto i:v[nod])
    {
        if(!b[i])
        {
            dfs(i);
        }
    }
}
int main()
{
    in>>n>>m;
    for(int i=1;i<=m;i++)
    {
        in>>x>>y;
        v[y].pb(x);
        v[x].pb(y);
    }
    for(int i=1;i<=n;i++)
    {
        if(!b[i])
        {
            cont++;
            dfs(i);
        }
    }
    out<<cont;
    return 0;
}