#include <cstdio>
#include <algorithm>
#include <cstring>
#include <vector>
#define maxN 1000002
using namespace std;
int n, m;
bool viz[maxN];
vector < int > V[maxN];
void read()
{
    int a, b, i;

    freopen("dfs.in", "r", stdin);
    freopen("dfs.out", "w", stdout);
    scanf("%d %d", &n, &m);
    for (i = 1; i <= m; ++ i)
    {
        scanf("%d %d", &a, &b);
        V[a].push_back(b);
        V[b].push_back(a);
    }
}
void dfs(int x)
{
    int i;
    for (i = 0; i < V[x].size(); ++ i)
        if (!viz[V[x][i]])
    {
        viz[V[x][i]] = 1;
        dfs(V[x][i]);
    }
}
void write()
{
    int i, nr = 0;
    for (i = 1; i <= n; ++ i)
        if (!viz[i])
    {
        ++ nr;
        viz[i] = 1;
        dfs(i);
    }
    printf("%d", nr);
}
int main()
{
    read();
    write();
    return 0;
}