#include <fstream>
#include <vector>

#define lim 100005

using namespace std;

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

vector <int> v[lim];

int n, m, cate;

bool valid[lim];

void read() {
    in >> n >> m;
    for(int i = 1; i <= m; ++i) {
        int x, y;
        in >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
}

void dfs(int x) {
    valid[x] = 1;
    //out << x << ' ';
    for(int i = 0; i < v[x].size(); ++i)
        if(valid[v[x][i]] == 0)
             dfs(v[x][i]);
}

int main()
{
    read();
    for(int i=1; i<=n; ++i)
        if(valid[i] == 0)
            ++cate,
            dfs(i);
    out << cate;
    return 0;
}