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

FILE *in, *out;

using namespace std;

struct nod
{
    int val = 1;
    vector<int> muchii;
};

nod graf[100001];

void dfs(int nodo)
{
    for(vector<int>::iterator it = graf[nodo].muchii.begin(); it != graf[nodo].muchii.end(); it++) {
        if(graf[*it].val == 1) {
            graf[*it].val = 0;
            dfs(*it);
        }
    }
}

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);
        graf[a].muchii.push_back(b);
        graf[b].muchii.push_back(a);
    }
    conex = 0;
    for(i = 1; i <= n; i++) {
        if(graf[i].val == 1) {
            dfs(i);
            conex++;
        }
    }

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

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