#include <iostream>
#include <fstream>
#include <list>
#define LIM 200000
using namespace std;

ifstream in("dfs.in");
ofstream out("dfs.out");

int n,m;
bool seen[LIM];

struct G{
    list <int> edge;
}graph[LIM];

void read(){
    in>>n>>m;
    int x,y;
    for(int i=0;i<m;i++){
        in>>x>>y;
        graph[x].edge.push_back(y);
        graph[y].edge.push_back(x);
    }
}

int DFS (int vertex){
    if(seen[vertex]) return 0;
    seen[vertex]=true;
    for(list<int>::iterator it=graph[vertex].edge.begin();it!=graph[vertex].edge.end();++it)
        DFS(*it);
    return 1;
}

int main()
{
    read();
    int s=0;
    for(int i=1;i<=n;i++){
        s+=DFS(i);
    }
    out<<s;

    return 0;
}