#include <iostream>
#include<stdio.h>
#include<stdlib.h>


using namespace std;
int *a[100001];
int n,m,viz[100001],nr;

void citire()
{
    freopen("dfs.in","r",stdin);
    scanf("%d %d",&n,&m);
    for(int i=1;i<=n;i++)
        {
            a[i]=(int *) realloc(a[i],sizeof(int));
            a[i][0]=0;
        }
    for(int i=1;i<=m;i++)
        {
            int x,y,z;
            scanf("%d %d",&x,&y);
            a[x][0]++;
            a[x]=(int *)realloc(a[x],(a[x][0]+1)*sizeof(int));
            a[x][a[x][0]]=y;
            a[y][0]++;
            a[y]=(int *)realloc(a[y], (a[y][0]+1)*sizeof(int));
            a[y][a[y][0]]=x;
        }

   /*for(int i=1;i<=n;i++)
        for(int j=1;j<=a[i][0];j++)
            cout<<i<<" "<<a[i][j]<<endl;*/
}

void dfs(int x)
{
    viz[x]=1;
    for(int  i=1;i<=a[x][0];i++)
        if(viz[a[x][i]]==0)
            dfs(a[x][i]);
}

int main()
{
    citire();
    for(int k=1;k<=n;k++)
        if(viz[k]==0)
            {
                nr++;
                dfs(k);
            }
    freopen("dfs.out","w",stdout);
    printf("%d",nr);
    return 0;
}