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

#define Nmax 100005

using namespace std;
int N,M,ncc;
vector<int> G[Nmax];
bitset<Nmax> used;

void read()
{
    scanf("%d%d",&N,&M);
    int a,b;
    for(int i = 1; i <= M; ++i)
    {
        scanf("%d%d",&a,&b);
        G[a].push_back(b);
        G[b].push_back(a);
    }
}

void DFS(int k)
{
    used[k] = 1;
    for(vector<int>::iterator it = G[k].begin(); it != G[k].end(); ++it)
        if(!used[*it])
            DFS(*it);
}

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

    read();
    for(int i = 1; i <= N; ++i)
        if(!used[i])
            DFS(i),++ncc;
    printf("%d\n",ncc);

    return 0;
}