#include <iostream>
#include <cstdio>
using namespace std;

const int N = 100001;
const int M = 2*N;
int lst[N],vf[2*M],urm[2*M],n,nr;
bool visited[N];

void adauga(int x, int y){
    vf[++nr] = y;
    urm[nr] = lst[x];
    lst[x] = nr;
}

void dfs(int x){
    visited[x] = true;
    for(int p=lst[x]; p!=0; p=urm[p]){
        int next = vf[p];
        if(!visited[next])
            dfs(next);
    }
}

int main()
{
    FILE *fin, *fout;
    int n,m,i,x,y,ans;
    fin = fopen("dfs.in","r");
    fout = fopen("dfs.out","w");
    fscanf(fin,"%d %d",&n,&m);
    for(i=0; i<m; i++){
        fscanf(fin,"%d %d",&x,&y);
        adauga(x,y);
        adauga(y,x);
    }
    ans = 0;
    for(i=1; i<=n; i++)
        if(!visited[i]){
            ans++;
            dfs(i);
        }
    fprintf(fout,"%d\n",ans);
    fclose(fin);
    fclose(fout);
    return 0;
}