#include <iostream>
#include <fstream>

using namespace std;

int a[100001][100001], v[100001], n, m, nr;

ifstream f ("dfs.in");
ofstream g ("dfs.out");

void df (int vf)
{
    int i;
    v[vf] = nr;
    for (i = 1; i <= n; i++)
        if (a[i][vf] == 1 && v[i] == 0)
            df(i);
}

int main()
{int i, j, k;
f >> n >> m;
for (k = 1; k <= m; k++)
{
    f >> i >> j;
    a[i][j] = a[j][i] = 1;
}
for (i = 1; i <= n; i++)
    if (v[i] == 0)
    {
        nr++;
        df(i);
    }
g << nr;
return 0;
}