#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, cnt;

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

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

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

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

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