#include<cstdio>
#define NMAX 100001
using namespace std;

int n, m;
bool viz[NMAX];
struct nod
{
    int val;
    nod *next;
};

nod *L[NMAX];

inline void adauga(int x, int y)
{
    nod *p = new nod;
    p->val = y;
    p->next = L[x];
    L[x] = p;
}

void DFS(int x)
{
    nod *p = L[x];
    viz[x] = 1;
    while(p != NULL)
    {
        if(!viz[p->val])
            DFS(p->val);
        p = p->next;
    }
}

void Read()
{
    int x, y, i;
    FILE *fin = fopen("dfs.in","r");
    fscanf(fin,"%d%d",&n,&m);
    for(i=1; i<=m; i++)
    {
        fscanf(fin,"%d%d",&x,&y);
        adauga(x,y);
        adauga(y,x);
    }
    fclose(fin);
}

int main()
{
    Read();
    FILE *fout = fopen("dfs.out","w");
    int nrc = 0, i;
    for(i=1; i<=n; i++)
        if(!viz[i])
        {
            ++nrc;
            DFS(i);
        }
    fprintf(fout,"%d\n",nrc);
    fclose(fout);
    return 0;
}