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

const int maxn = 100001;

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

int n, m;
vector<int> a[maxn];
int v[maxn];

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

    int x, y;
    for ( int i = 1; i <= m; ++i )
    {
        fscanf(in, "%d %d", &x, &y);
        a[x].push_back(y);
        a[y].push_back(x);
    }
}

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


    for (int i = 0; i < a[nod].size(); ++i)
    {
        if ( !v[ a[nod][i] ] )
            df(a[nod][i]);
  }
}

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;
}