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

const int dmax = 100000;
const int dim = 1000000;

int lst[dmax+1];
int vf[2*dim + 1];
int urm[2*dim + 1];
int nr;

int N,M;

bool viz[dmax+1];
int NR;

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

void DFS(int x)
{
    int p,y;

    viz[x] = true;

    //printf("%d ", x);

    p = lst[x];

    while(p)
    {
        y = vf[p];

        if(viz[y] == false) DFS(y);

        p = urm[p];
    }

}

int main()
{
    freopen("dfs.in", "r", stdin);
    freopen("dfs.out", "w", stdout);

    int i, x, y;

    scanf("%d %d", &N, &M);

    for(i = 1; i <= M; i++)
    {
        scanf("%d %d", &x, &y);

        adauga(x,y);
        adauga(y,x);
    }

    for(i = 1; i <= N; i++)
        if(viz[i] == false)
        {
            NR++;
            DFS(i);
            //printf("\n");
        }

    printf("%d", NR);

    return 0;
}