#include <fstream>
using namespace std;

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

bool viz[1001];
bool a[1001][1001];
int n, m;

void DFS(int nod)
{
    viz[nod] = 1;
    for(int i = 1; i <= n; i++)
        if(a[nod][i] && !viz[i])
            DFS(i);
}

int main()
{
    f >> n >> m;

    for(int k = 1; k <= m; k++)
    {
        int x, y;
        f >> x >> y;
        a[x][y] = a[y][x] = 1;
    }

    int nrc = 0;
    for(int i = 1; i <= n; i++)
        if(!viz[i])
            DFS(i), nrc++;

    g << nrc;
    return 0;
}