#include <bits/stdc++.h>
using namespace std;
vector<int> E[100005];
bool D[100005];
void DFS(int k){
    stack<int> Q;
    Q.push(k);
    D[k]=1;
    while(!Q.empty()){
        int X=Q.top();
        for(auto it : E[X])
            if(D[it]==0){
                D[it]=1;
                Q.push(it);
            }
        Q.pop();
    }
}
int main(){
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    int n,m;
    scanf("%d %d",&n,&m);
    for(int i=1;i<=m;++i){
        int st,dr;
        scanf("%d %d",&st,&dr);
        E[st].push_back(dr);
        E[dr].push_back(st);
    }
    int ct=0;
    for(int i=1;i<=n;++i){
        if(D[i]==0){
            ++ct;
            DFS(i);
        }
    }
    printf("%d\n",ct);
    return 0;
}