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

FILE *in, *out;

const int dmax = 1000;

int N,M;
bool A[dmax+1][dmax+1]; bool viz[dmax+1];
int NR;

void DFS(int nod)
{
    viz[nod] = 1;

    for(int i=1; i<=N; i++)
        if(viz[i] == false && A[nod][i] == true) DFS(i);
}

void CITIRE()
{
    in = fopen("dfs.in", "r");
    out = fopen("dfs.out", "w");

    fscanf(in, "%d %d", &N,&M);
    for(int i=1; i<=M; i++)
    {
        int x,y;
        fscanf(in, "%d %d", &x,&y);

        A[x][y] = A[y][x] = true;
    }
}

int main()
{
    CITIRE();

    for(int i=1; i<=N; i++)
        if(viz[i] == false) { NR++; DFS(i); }

    fprintf(out, "%d", NR);

    return 0;
}