#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

ifstream fin("dfs.in");
ofstream fout("dfs.out");

int n, m, sol;
bool a[1005][1005], viz[100005];

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

int main()
{
    fin>>n>>m;
    int x, y;
    while(m--)
    {
        fin>>x>>y;
        a[x][y] = a[y][x] = 1;
    }

    for(int i=1; i<=n; i++)
        if(!viz[i])
        {
            sol++;
            DFS(i);
        }

    fout<<sol;
    return 0;
}