#include <cstdio>

using namespace std;

const int MAX_N = 100000, MAX_M = 200000;

FILE *in, *out;

int lst[MAX_N+1], urm[MAX_M+1], vf[MAX_M];
int nr;

void add(int x, int y)
{
    nr++;
    vf[nr] = y;
    urm[nr] = lst[x];
    lst[x] = nr;
}

bool viz[MAX_N+1];

void dfs(int x)
{
    int p = lst[x];
    viz[x] = true;
    while(p != 0)
    {
        if(!viz[vf[p]])
            dfs(vf[p]);
        p = urm[p];
    }
}

int main()
{
    in = fopen("dfs.in", "r");
    out = fopen("dfs.out", "w");

    int n, m;
    int x, y;
    int nrc;
    fscanf(in, "%d%d", &n, &m);
    for(int i = 1; i <= m; i++)
    {
        fscanf(in, "%d%d", &x, &y);
        add(x,y);
        add(y,x);
    }
    for(int i = 1; i <= n; i++)
    {
        if(!viz[i])
        {
            nrc++;
            dfs(i);
        }
    }
    fprintf(out, "%d", nrc);
    fclose(in);
    fclose(out);
    return 0;
}