#include <fstream>
#include <algorithm>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");

int viz[100002], n;
int vec[100002][100002];

void dfs(int rad)
{
    viz[rad] = 1;
    for (int i = 1; i <= n; i++)
        if (viz[i] == 0 && vec[rad][i] == 1) {
            dfs(i);
        }
}

int main()
{ 
    int m, i, x, y, nr=0;
    fin >> n >> m;
    for(i=0;i<m;++i)
    {
	fin >> x >> y;
	vec[x][y] = vec[y][x] = 1;  
    }
    for (i = 1; i <= n; i++)
    {
        if (viz[i] == 0)
        {
            nr++;
            dfs(i);
        }
    }
    fout << nr;
    fin.close();
    fout.close();
    return 0;
}