#include <cstdio>
#include <vector>

#define NMAX 100001

using namespace std;

vector < int > G[NMAX];

int n;
int viz[NMAX];

void read()
{
    int m;
    int x;
    int y;

    freopen("dfs.in", "r", stdin);

    scanf("%d %d\n", &n, &m);
    while(m --)
    {
        scanf("%d %d\n", &x, &y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

void dfs(int nod)
{
    viz[nod] = viz[0];

    unsigned int m = G[nod].size();
    for(unsigned int i = 0; i < m; ++ i)
        if(viz[G[nod][i]] == 0)
            dfs(G[nod][i]);
}

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

int main()
{
    read();
    solve();

    freopen("dfs.out", "w", stdout);
    printf("%d\n", viz[0]);

    return 0;
}