#include <iostream>
#include <stdio.h>
using namespace std;
int a[10001][10001], n, m, viz[1000001], nr;

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

void DFS(int x)
{
    viz[x] = 1;
    for (int i = 1; i <= n; i++)
        if (!viz[i] && a[x][i])
            DFS(i);
}

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