#include<cstdio>
#define N_MAX 100000
using namespace std;

bool used[N_MAX+1];
int n, m, nrc;
struct nod
{
    int val;
    nod *next;
};

nod *L[N_MAX+1];

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

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

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

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