#include <cstdio>

const int maxn = 100001;

FILE *in = fopen("dfs.in","r"), *out = fopen("dfs.out","w");

struct graf
{
    int nod;
    graf *next;
};

int n, m;
graf *a[maxn];
int v[maxn];

void add(int x, int y)
{
    graf *q = new graf;
    q->next = a[x];
    q->nod = y;
    a[x] = q;
}

void read()
{
    fscanf(in, "%d %d", &n, &m);

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

void df(int nod)
{
    v[nod] = 1;

    graf *q = new graf;
    q = a[nod];
    while ( q )
    {
        if ( !v[ q->nod ] )
            df(q->nod);

        q = q->next;
    }
}

int main()
{
    read();

    int nr = 0;
    for ( int i = 1; i <= n; ++i )
        if ( !v[i] )
            df(i), ++nr;

    fprintf(out, "%d\n", nr);

    return 0;
}