#include<bits/stdc++.h>

using namespace std;

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

vector<int> freq;
//map<int,vector<int>> adjList;
vector<int> adjList[100001];

void DFS(int x){
    int i;

    for(i=0;i<adjList[x].size();++i){
        if(freq[adjList[x][i]-1]==0){
            freq[adjList[x][i]-1]++;
            //cout<<adjList[x][i]<<' ';
            DFS(adjList[x][i]);
        }
        
    }
}
int main(){
    int n,m,a,b,count=0;
    
    int i,j;
    f>>n>>m;
    for(i=0;i<m;++i){
        f>>a>>b;
        adjList[a].push_back(b);
        adjList[b].push_back(a);
    }

    for(i=0;i<n;++i){
        freq.push_back(0);
    }
        for(i=0;i<freq.size();++i){
            if(freq[i]==0){
                freq[i]++;
                count++;
                DFS(i+1);
            }
                
        }
    

    g<<count;
    return 0;
}