#include <cstdio>
#include <vector>
using namespace std;
const int NMAX = 100000;
vector <int> g[NMAX + 5];
int viz[NMAX + 5];
inline void dfs(int x)
{
    viz[x] = 1;
    for (int i = 0; i < g[x].size(); ++i)
        if (viz[g[x][i]] == 0)
            dfs(g[x][i]);
}
int main()
{
    freopen("dfs.in", "r", stdin);
    freopen("dfs.out", "w", stdout);
    int n, m, x, y, ans;
    scanf("%d %d", &n, &m);
    for (int i = 1; i <= m; ++i)
    {
        scanf("%d %d", &x, &y);
        g[x].push_back(y);
        g[y].push_back(x);
    }

    ans = 0;
    for (int i = 1; i <= n; ++i)
        if (viz[i] == 0)
        {
            dfs(i);
            ++ans;
        }
    printf("%d\n", ans);
    return 0;
}