#include <bits/stdc++.h>

using namespace std;

int n, m, x, y, k;
int viz[100005];
int L[100005];
int vec[200005];
int urm[200005];

void bfs(int in) {
    queue<int> q;
    q.push(in);
    viz[in] = k;
    while(!q.empty()) {
        in = q.front();
        q.pop();
        for(int poz = L[in]; poz; poz = urm[poz]) {
            if(!viz[vec[poz]]) {
                q.push(vec[poz]);
                viz[vec[poz]] = k;
            }
        }
    }
}

int main()
{
    FILE *f = fopen("dfs.in", "r");
    FILE *g = fopen("dfs.out", "w");
    fscanf(f, "%d %d", &n, &m);
    for(int i = 1; i <= m; i ++) {
        fscanf(f, "%d %d", &x, &y);
        vec[i * 2 - 1] = y;
        urm[i * 2 - 1] = L[x];
        L[x] = i * 2 - 1;
        vec[i * 2] = x;
        urm[i * 2] = L[y];
        L[y] = i * 2;
    }
    for(int i = 1; i <= n; i ++) {
        if(!viz[i]) {
            k ++;
            bfs(i);
        }
    }
    fprintf(g, "%d\n", k);
    return 0;
}