#include <bits/stdc++.h>

using namespace std;

int n, m, x, y, k;
struct node{
    node *next;
    int inf;
};
node *V[100005];
int viz[100005];

void add(node *&start, int inf) {
    node *one = new node;
    one->inf = inf;
    one->next = start;
    start = one;
}

void bfs(int in) {
    queue<int> q;
    q.push(in);
    viz[in] = k;
    while(!q.empty()) {
        in = q.front();
        q.pop();
        for(node *p = V[in]; p; p = p->next) {
            if(!viz[p->inf]) {
                q.push(p->inf);
                viz[p->inf] = 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);
        add(V[x], y);
        add(V[y], x);
    }
    for(int i = 1; i <= n; i ++) {
        if(!viz[i]) {
            k ++;
            bfs(i);
        }
    }
    fprintf(g, "%d\n", k);
    return 0;
}