#include <cstdio>
#include <vector>
#include <bitset>

std::vector<int> graph[100002];
std::bitset<100002> vis;

void bfs(int start){
    std::vector<int> que;

    vis[start] = 1;
    que.push_back(start);
    for (unsigned i=0; i<que.size(); ++i){
        for (unsigned j=0; j<graph[que[i]].size(); ++j){
            if (!vis[graph[que[i]][j]]){
                vis[graph[que[i]][j]] = 1;
                que.push_back(graph[que[i]][j]);
            }
        }
    }
}

int main()
{
    int N, M;
    int sol = 0;

    freopen("dfs.in", "r", stdin);
    freopen("dfs.out", "w", stdout);

    scanf("%d %d", &N, &M);
    for (int i=0; i<M; ++i){
        int x, y;

        scanf("%d %d", &x, &y);
        graph[x].push_back(y);
        graph[y].push_back(x);
    }

    for (int i=1; i<=N; ++i){
        if (!vis[i]){
            bfs(i);
            ++sol;
        }
    }
    printf("%d", sol);
    return 0;
}