#include<stdio.h>
#include<vector>

FILE *in, *out;

using namespace std;

vector<int> dfs[200001];
int viz[200001];

void dfsalg(int nod)
{
    viz[nod] = 1;
    for(int i = 0; i < dfs[nod].size(); i++) {
        if(viz[dfs[nod][i]] == 0) {
            dfsalg(dfs[nod][i]);
        }
    }
}

int main ()
{
    int n, m, i, conex, a, b;

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

    fscanf(in, "%d%d", &n, &m);

    for(i = 0; i < m; i++) {
        fscanf(in, "%d%d", &a, &b);
        dfs[a].push_back(b);
        dfs[b].push_back(a);
    }
    conex = 0;
    for(i = 1; i <= n; i++) {
        if(viz[i] == 0) {
            dfsalg(i);
            conex++;
        }

    }

    fprintf(out, "%d", conex);

    fclose(in);
    fclose(out);
    return 0;
}