#include<cstdio>
#include<vector>
#define MAX_N 100000
using namespace std;

vector<int>g[MAX_N+1];
bool used[MAX_N+1];
int n, m, ans;

void readGraph() {
    int x, y;
    FILE* fin = fopen("dfs.in","r");
    fscanf(fin,"%d%d",&n,&m);
    for(int i = 0; i < m; i++) {
        fscanf(fin,"%d%d",&x,&y);
        g[x].push_back(y);
        g[y].push_back(x);
    }
    fclose(fin);
}

void DFS(int node) {
    used[node] = true;
    for(auto i : g[node])
        if(!used[i])
            DFS(i);
}

void DFS_master() {
    for(int i = 1; i <= n; i++) {
        if(!used[i]) {
            DFS(i);
            ans++;
        }
    }
}

void printComp() {
    FILE* fout = fopen("dfs.out","w");
    fprintf(fout,"%d\n",ans);
    fclose(fout);
}

int main() {
    readGraph();
    DFS_master();
    printComp();
    return 0;
}